[Mywifes335]

OK, finally. Here are the details of the exhaust:

1. ER Catless DP
2. Removed stock resonator
3. Removed fiberglass packing from chamber 1 and 3 and perforated tube replaced with straight tubing
4. External bypass installed prior to muffler into the driver's side tip
5. 4" SS tips installed and welded
6. All tubing used is 409 stainless steel and MIG welded

Similar to Marv, I came to this "system" through first installing the ER catless DP then 3 trial and error exhaust modifications and fitments.

The first step was installing the ER DP, which added more sound at WOT and made the overrun more noticeable. No drone and barely louder than stock in the cabin.

The second step was installing the external bypass just ahead of the stock muffler into the driver's side tip. At the same time, the flapper valve was left open and the actuator was disconnected and tied off. No noticeable change in sound over the first step.

The third step was using a plasma cutter to open up the 1st and 3rd chambers of the stock exhaust and removing the fiberglass packing. Then the perf core in the 3rd chamber was replaced with straight pipe. The muffler was then welded back together. This mod made a noticeable difference in the overall sound while cruising - you can actually hear a hint of the straight 6 sound. At WOT the car was louder as well. The overrun became very pronounced, the cracks and pops sounded like muted gunshots. No drone. Idle was smooth and quiet after warm up (RPMs drop).

The last step was removing the resonator and replacing the section with a straight 409 stainless steel pipe. Then, 2 4" 304 stainless exhaust tips were welded on. The car got just a bit louder than before overall. However, the exhaust note during idle finally sounded more fitting for a sports car.

Result: very happy. I give credit to the guy who did this first in the F30 as well as dd1981. Also, Starvmarv for the inspiration. Finally, Denny and the guys at Mufflex in Trenton, NJ for all the patience and Fabwork. According to Mufflex, retail for this exact setup in 409 stainless would run somewhere in the mid-$600 range.

Pics:

Unable to upload video directly. Please advise (first time).