After researching the OEM mod on here, I decide to have it done to my E93 M3 and wanted to take this opportunity to do a quick write up on my experience. I spend most of my time in between the GTA area and Upstate NY area so I had the option of getting it done either in Canada or the US. The next step was to get more information from local shops on either side of the border. I got in touch with shops as far as 4-5 hours away from me and ultimately decided to go with Bimmersport Automotive, located in Mississauga, ON.
Right from the start, the communication was smooth and Jon was always very prompt with replying and answering questions. They hadn't done this ACM inspired mod before but I had a good feeling about the quality of their work especially after having read so many positive reviews about them and having friends who trust them completely to care for their BMWs.
I decided to go with the ACM version which involves bypassing the entire center chamber completely. Bimmerpost was able to do a slightly modified version of this ACM mod and as you can see from the pics they posted, they did a very nice clean job. In my opinion the difference in sound is NIGHT and DAY. There are individuals who have posted that similar versions of this mod give you only ~25% increase in sound at revs >3000. I would say that my exhaust is at least 50% louder now at >3500 rpm and 100% louder > 4500 rpm. Have not really rev'd the car up to 8000 yet as she's still a baby with less than 2500 miles.
At revs below 2500 rpm, there is very little difference in sound compared to the unmodified OEM exhaust. The most noticeable difference to me was not just the loudness but also the exhaust note of the car. It really does sound exotic and as others have said, you really have to hear it in person! They had an E90 M3 with an Active Autowerke Signature exhaust system and in comparing exhausts, the OEM exhaust mod seemed just as loud but with a deeper howl to it. The total job took longer than we had anticipated because we had to wait for the paint guy to arrive with the paint. I would say if you plan on waiting around like I did, to give yourself 4-5 hours.
I have not driven the car since the drive back, but on my 45 min car ride back I didn't noticed any drone. Sound quality inside the car is definitely more pronounced as you are cruising along the highway but definitely manageable and not overpowering.
I’m very glad I decided to get this done and thanks again to Jon, Charlie and the rest of the Bimmersport Automotive guys! I know there are quite a few of you on here especially in the GTA that are sitting on the fence about having this done. The bottom line is that this is the most well spent money ever on a mod for me and OEM bypass exhaust mod sounds absolutely effing AMAZING!
I will be posting up video clips shortly but if you’re ever in the area and want to have a listen for yourself to decide, feel free to drop me a line.