[MerlinMc]

I have driven an M235i for the past 4 years and have been very happy with the vehicle. Only major mod was moving to a “square” wheel and tire set up (summer performance tire and snows in winter). Car is a daily driver though I like to go to the track to drive fast (no competitions) in a safe setting. I now have a 2020 M240i on order. We don't know what port-installed options are available yet.

The purpose of this email is to seek opinions on exhaust alternatives. I have searched/scoured the various exhaust threads and founds lots of useful information. I would like to get the latest thinking, especially for a M240i with the B58 engine.

Objectives

Sound. Want improved and a little louder sound, but not too loud.

Power. Would like to improve HP & torque, if only a little.

Tune. Would like to be compatible with a tune if I decide to do that.

Fit. Want stock fit with no modifications required.

Cost. Always a consideration.

Questions

Alternatives. I am considering: MPE Exhaust, Dinan Exhaust, Dinan Downpipe either with or without Dinan or other (even stock) exhaust. Recommendations on these given objectives? Am I missing any strong alternatives?

Sport Cat. I have a FabSpeed for my M235i that I never installed. I assume this will not work with the B58 engine, correct? Other sport cat recommendations? We have emissions testing every few years here in WA state, so needs to pass that test. The CG Precision DS-1 appears to be an alternative for the B58.

Diffuser. Thoughts on the M or other diffusers? Can these be installed without removing the rear bumper and still get a clean, minimal gap look? Will all of the alternatives mentioned above work with the M diffuser.

Thank you in advance for your thoughts. Very much appreciated.

[XutvJet]

The sport cat alone will give you comparable HP and TQ to a M240. The sport cat is good for around 15whp/25wtq with no tuning needed. Most importantly, it gains power across the entire powerband which is what makes the car faster. It will also add more exhaust volume.

At the least, consider installing that first because all the M240 really offers above the M235 is a bit more stock power, unless you're wanting the updated interior in the 2018+ cars and different headlight options and LED taillights. It's very easy to get an M235 to out gun an M240 with just a DP and flash tune.

The N55 FS sport cat will not work on the B58. Plus, B58s don't really make much in the way of extra power with a DP.

The MP diffuser can easily be installed without removing the bumper.

The MPE is by far the best fitting exhaust available. Most others, especially Dinan, can have wonky exhaust fitment.

The sound of the MPE, especially on the M235, is amazing. It's not overly loud, but it sounds fluid, semi-exotic, lots of burbles, and minimal cabin volume intrusion when the windows are up.

[MerlinMc]

Originally Posted by XutvJet

The sport cat alone will give you comparable HP and TQ to a M240. The sport cat is good for around 15whp/25wtq with no tuning needed. Most importantly, it gains power across the entire powerband which is what makes the car faster. It will also add more exhaust volume.

At the least, consider installing that first because all the M240 really offers above the M235 is a bit more stock power, unless you're wanting the updated interior in the 2018+ cars and different headlight options and LED taillights. It's very easy to get an M235 to out gun an M240 with just a DP and flash tune.

The N55 FS sport cat will not work on the B58. Plus, B58s don't really make much in the way of extra power with a DP.

The MP diffuser can easily be installed without removing the bumper.

The MPE is by far the best fitting exhaust available. Most others, especially Dinan, can have wonky exhaust fitment.

The sound of the MPE, especially on the M235, is amazing. It's not overly loud, but it sounds fluid, semi-exotic, lots of burbles, and minimal cabin volume intrusion when the windows are up.

Thanks very much for your thoughts. I am mainly wanting a different color, the updated interior and the bigger screen. Usually swap my vehicles every 4 years or so and there is nothing available now that I like better than the F22 that's not crazy expensive.

[marcthedark]

Originally Posted by MerlinMc

I have driven an M235i for the past 4 years and have been very happy with the vehicle. Only major mod was moving to a “square” wheel and tire set up (summer performance tire and snows in winter). Car is a daily driver though I like to go to the track to drive fast (no competitions) in a safe setting. I now have a 2020 M240i on order. We don't know what port-installed options are available yet.

The purpose of this email is to seek opinions on exhaust alternatives. I have searched/scoured the various exhaust threads and founds lots of useful information. I would like to get the latest thinking, especially for a M240i with the B58 engine.

Objectives

Sound. Want improved and a little louder sound, but not too loud.

Power. Would like to improve HP & torque, if only a little.

Tune. Would like to be compatible with a tune if I decide to do that.

Fit. Want stock fit with no modifications required.

Cost. Always a consideration.

Questions

Alternatives. I am considering: MPE Exhaust, Dinan Exhaust, Dinan Downpipe either with or without Dinan or other (even stock) exhaust. Recommendations on these given objectives? Am I missing any strong alternatives?

Sport Cat. I have a FabSpeed for my M235i that I never installed. I assume this will not work with the B58 engine, correct? Other sport cat recommendations? We have emissions testing every few years here in WA state, so needs to pass that test. The CG Precision DS-1 appears to be an alternative for the B58.

Diffuser. Thoughts on the M or other diffusers? Can these be installed without removing the rear bumper and still get a clean, minimal gap look? Will all of the alternatives mentioned above work with the M diffuser.

Thank you in advance for your thoughts. Very much appreciated.

Catback
Power > all will add a little but nothing you will notice
Tune > everything is "compatible" with a tune
Fit > as most are designed as a stock replacement you should have no problem
So decide on Sound (and $$) alone. Options you have missed
- resonator delete
- Dinan midpipe
- Stock modification (search UK boards they do it a lot)
- Remus, BCS (?) and probably some others

Downpipe will add sound and power to a degree that might be actually noticeable (throttle response etc) based on de-cat, 200 cell, 400 cell
BTW Dinan doesn't produce any downpipe

For Sound > catback/ resonator delete/..... as loud as you like it
For Power > tune
DP I would only consider if you can't live with 90-95% of optimum and need to free up the last 5-10% of HP

[Razzback]

If you go the Dinan Route, I would suggest the axel back first. If you're not satisfied with the sound, you can go for the mid pipe, but I found the combo obnoxiously loud for a daily driver, and eventually installed the stock mid pipe. Sounds better than stock, but not annoying, imo. Also the exhaust tips are welded on, so there's no adjustment for length. It's designed to be used with the stock rear, so if you get the m performance diffuser, your tips wont be as exposed. I personally had fitment issues with the exhaust sitting low... but I seem to be in the minority.

Two other options I like would be the m performance exhaust which has comparable sound and you can adjust the tips, or the Remus cat back (sport) with the resonator. The latter being about twice as expensive, and more exotic sounding imo.

[MerlinMc]

Originally Posted by Razzback

If you go the Dinan Route, I would suggest the axel back first. If you're not satisfied with the sound, you can go for the mid pipe, but I found the combo obnoxiously loud for a daily driver, and eventually installed the stock mid pipe. Sounds better than stock, but not annoying, imo. Also the exhaust tips are welded on, so there's no adjustment for length. It's designed to be used with the stock rear, so if you get the m performance diffuser, your tips wont be as exposed. I personally had fitment issues with the exhaust sitting low... but I seem to be in the minority.

Two other options I like would be the m performance exhaust which has comparable sound and you can adjust the tips, or the Remus cat back (sport) with the resonator. The latter being about twice as expensive, and more exotic sounding imo.

Super information; thank you very much.

I am leaning towards getting the m performance diffuser. My current M235i is a daily driver and the 240i will be as well. I want a better sound but not too loud.

[Mehim]

Originally Posted by MerlinMc

Super information; thank you very much.

I am leaning towards getting the m performance diffuser. My current M235i is a daily driver and the 240i will be as well. I want a better sound but not too loud.

The resonator deletes sound good imo, price is right too.

[Rockstar1487]

Sound: I started with the dinan mid and axel back. I severely disliked it. Like others stated, fitment was wonky. I just did not particularly care for the sound. It was to quiet for me. Louder than the stock exhaust but still quiet. I came out of a n54 135i with n55 mids and mpe, it sound amazing, loud AF but not over the top. I eventually got the full akrapovic exhaust, dp, mid, and axel back....it is perfect. Honestly, sound comes down to personal preference, you just gotta find what suits your needs. Also the akrapovic downpipes is a 200 CEL catted, does not cause check engine light, should help with your inspection purposes.

Power: As stated, tune is everything, along with other supporting mods...full exhaust, intake, charge pipe, etc. I have a jb4 right now and love the thing but will be going for a flash in the near future.

Diffuser: I haven't gotten one yet, and again I think it comes down to what your prefer and how much you want to spend. I am planning on getting the Dinmann carbon fiber one, I like the way it looks the most over all the rest but have not gotten around to buying it. I do like the way the MP diffuser looks but prefer carbon fiber.

[mblaucoupe135]

Originally Posted by MerlinMc

I have driven an M235i for the past 4 years and have been very happy with the vehicle. Only major mod was moving to a “square” wheel and tire set up (summer performance tire and snows in winter). Car is a daily driver though I like to go to the track to drive fast (no competitions) in a safe setting. I now have a 2020 M240i on order. We don't know what port-installed options are available yet.

The purpose of this email is to seek opinions on exhaust alternatives. I have searched/scoured the various exhaust threads and founds lots of useful information. I would like to get the latest thinking, especially for a M240i with the B58 engine.

Objectives

Sound. Want improved and a little louder sound, but not too loud.

Power. Would like to improve HP & torque, if only a little.

Tune. Would like to be compatible with a tune if I decide to do that.

Fit. Want stock fit with no modifications required.

Cost. Always a consideration.

Questions

Alternatives. I am considering: MPE Exhaust, Dinan Exhaust, Dinan Downpipe either with or without Dinan or other (even stock) exhaust. Recommendations on these given objectives? Am I missing any strong alternatives?

Sport Cat. I have a FabSpeed for my M235i that I never installed. I assume this will not work with the B58 engine, correct? Other sport cat recommendations? We have emissions testing every few years here in WA state, so needs to pass that test. The CG Precision DS-1 appears to be an alternative for the B58.

Diffuser. Thoughts on the M or other diffusers? Can these be installed without removing the rear bumper and still get a clean, minimal gap look? Will all of the alternatives mentioned above work with the M diffuser.

Thank you in advance for your thoughts. Very much appreciated.

I have the MPE with Dinan midpipe and love it! not too loud but not too quiet either. prior to getting the midpipe I just had the MPE and it was way too quiet for my tastes especially inside with the windows closed and stereo on I could barely hear it. midpipe fixed that!

[dradernh]

Originally Posted by Rockstar1487

Honestly, sound comes down to personal preference, you just gotta find what suits your needs.

^ This.

The trick is to find out what that is without buying three systems along the way. Ask me how I know.

My hearing is pretty well shot, so having a louder exhaust isn't what grabs me, except in one context: at the track in DSC OFF mode the car is virtually silent compared to what I'm used to, and so far that's made rev-matching downshifts a bit of a problem.

Looking at the prices of 2 series aftermarket systems, I'll likely go with a custom system if I decide making the car louder makes sense. That way I can have the connections fab'd with V-band clamps. That will make muffler changes from street-to-track and back quick and easy. A muffler from Magnaflow, Flowmaster, or SuperTrapp should work.

[BMWZ4]

As some have suggested, do the res-delete!! I did this on my '16 235 and it was awesome. I'm actually going to my local muffler shop this Saturday to do it again on '19 X3 M40i.

[Rockstar1487]

Originally Posted by dradernh

^ This.

The trick is to find out what that is without buying three systems along the way. Ask me how I know.

THIS^^^^ lol.

I know that feeling hahahahaha. Youtube videos and poor audio quality on them only do so much justice.