My Impressions - OEM Exhaust Mod (M3 Convertible)
I am posting this mostly for people like me who are considering the OEM Exhaust Mod (non-perforated), as I thought it might be helpful. I have a 2013 M3 convertible and my previous 3 cars were non-modified E46 M3 convertibles. I really like the E46 M3 convertible's sound levels, in that I found the soft top allowed for a good amount of noise to enter the cabin. So when I get my E93 M3 Convertible, the biggest let down for me was how quiet the car was (you'll see that I posted several times about this). After listening to a few catback exhausts in-person (thanks to those who helped me out!), I decided to go with the OEM Exhaust Mod (non-perforated), mostly because it seemed to achieve the same results as most other exhausts at a fraction of the price. Importantly, I also liked the way it sounded (it sounds slightly different than most other exhausts IMO, at least on the outside).
Here's a quick summary of my thoughts. Please keep in mind that my primary goal was to have MORE cabin noise with the roof and windows up below 3k RPMs, as I found the car too quiet in city driving with the roof up:
ē Most important huge plus: It changed the character o the car completely, which was my most major disappointment with the M3 convertible. I felt like the E93 M3 Convertible was MUCH more disconnected from the roof and didn't satisfy me, as an enthusiast, during city driving that doesn't involve putting my foot all of the way down on the gas. This absolutely took care of that problem - it's like I'm driving a whole new car that is MUCH more fun to drive. I can now understand why many others have said this is the way the car should have come. I agree with that comment for the coupe but not necessarily for the convertible, at least when the roof's down (see my comments below on this).
ē Roof Up City Driving: Accomplished exactly what I had hoped in terms of extra noise in the cabin with the roof up, although it's a slight notch louder than I would have chosen, as it can still be heard while driving with the music/radio quite loud. On a scale of 1 to 10, if a stock car is 1 and a very loud car is 10 then this is probably a 6 in my best guess. It reminds me of the stock exhaust on an E64 M6 Convertible but 1 notch louder. Itís 1 notch louder than I would choose (optimally) but overall Iím pretty happy with it with the roof up.
ē Roof Up Highway: There is definitely some drone at 2100 + 3000 RPMs, and a very slight amount through most of the band when giving gas. If I did a lot of highway driving then I wouldnít be able to handle it and I would switch back. But thankfully I donít!
ē Roof Down City Driving: Itís definitely loud Ė louder than I anticipated Ė but itís not so loud that I canít have a conversation with someone at normal volume. But if I was able to choose then I would tone it down with the roof down. It might actually be too loud for my liking but I have only driven it once with the roof down so far so I'm not sure. Interestingly, coupe owners don't have to consider this so I can see why so many coupe owners like this mod, as I suspect some would find it far too loud if they had convertibles (at least with the roof down). I'm still reserving my final judgment for this category until next Spring, as that's when my roof will be down quite a lot (in Los Angeles).
ē General noise for others near the car: Iím still trying to assess this. Thus far 2 friends have told me it doesnít sound obnoxious, which is my major concern, but Iím still evaluating this. Ultimately Iíll probably have someone drive the car for me so I can hear it myself as it drives away. I'm very conservative so this is an important item for me. Still assessing this to be certain but so far it doesn't seem that bad... But I staying away from the loud upshifts in DCT 4-5 for now, as I suspect they might be loud on the outside!
ē Steering Wheel Vibration: Very minor steering wheel vibration when stopped. Not enough to annoy me but itís definitely there. It's clearly from the exhaust resonation.
I hope this feedback is helpful as it relates to your future conversations with others who are considering it. Overall I am happy with it so far, as it has made the car MUCH more fun to drive. I still need to get it used to it, especially with the roof down and as it relates to causing noise for others, but itís definitely a whole new experience, which I am happy about. I'm still going to take some more time to assess whether I will keep it due to the possible excessive noise with the roof down.
I hope some people find this helpful! A BIG thanks again to everyone who helped me out during this process!