[Runnin'Rich]

I’ve fitted the euro 130i sound generator to my e91 328i.
I could barely hear the difference.
I can only think the 130i must have less sound insulation so the driver can hear more.
I attached a hose from the sound generator and ran it out the hood into the drivers window. It sounded amazing, just like the Z4 sound generator that directly pipes through a factory hole in the firewall.
There is no hole in the e90 firewall so I attempted to pipe the sound closer to the driver. I cut a hole into the plastic which surrounds the wiper mechanism and piped the sound in there. This did not help much in terms of volume.

Mine is LHD, I know there is holes in the firewall for the RHD equivalent. But they are blocked by the ebox and exhaust heat shields.

Does anyone have an idea of where I could get a 1-2” hole in the firewall without cutting metal?

Thanks
PS I’m not interested in K&N filters or silicon elbows for more intake sound