I am extremely picky and I like to try new things. Exhausts for the E9X have been something I've tried a lot of. This is my 3rd M3, and I've had all versions thereof. (E90, E92, E93)
2011 E90 M3 DCT:
Magnaflow
Corsa
Riss Racing
Autobahn Exotics
Vanguard
Vanguard + Fabspeed X pipe (stock primary cats)
Akrapovic slip on + Fabspeed X pipe
Akrapovic slip on
Akrapovic Evolution
Challenge Sport X pipe + Akrapovic Slip on
Challenge Sport X pipe + Arqray titanium
Turner Test pipes + stock
Stock X pipe + BMW Performance exhaust
Turner Test pipes + BMW Performance Exhaust
Turner Test pipes + Arqray
Turner Test pipes + Innotech rear section
On my 2011 E93 M3 DCT:
Innotech rear section (doesn't fit with the E93's brace)
Akrapovic Slip on
Akrapovic w/ Turner Test Pipes (forgot about this combo last time!)
Eisenmann Sport
On my 2012 E92 M3 6MT:
MXP
Corsa
I've found that just about all exhausts sound good from outside the car when you are stomping on it. At high RPMs, the S65 sings a sweet sweet song. It's really easy to make an exhaust sound good from 6000-8500 rpm. Inside the car, the loud, resonator free, induction noise masks quiet exhausts over 5000 rpm. Ideally you'd want an exhaust that is very mellow and low rpms, and then gets really loud at high RPMs. It's a hard balance to find.
Let's get the bad stuff out of the way. The Corsa is no beauty queen. The cans hang down a bit, and the tips are a little small, resulting in a slightly dopey look. It's like wearing a tank top in April, you still have your winter fat layer underneath your skin, and you're pasty from not being out in the sun. You might describe it as quite ready to be seen by the outside world. It's not horrible and especially with the cans painted black, it's not the worst looking thing in the world, definitely better than stock... but it's not hugely pretty either.
The construction of the exhaust is nice, in my opinion. The welds are thick and ropey looking, but they aren't going anywhere. They have a certain hand made charm to them, they aren't icy cold TiG welds done by WALL-E, you're clearly supporting the US economy because some guy sitting in a factory, more than likely with a bad case of plumber's crack, welded this up. Excellent weld penetration, not too much bluing, etc... but not pretty. No polished pipes, here, this was made to get exhaust out from under the car, into the face of those behind you. Definitely not going to win any bling contests.
Installation is pretty standard. Not quite as easy as the Akrapovic, but it lines up and fits nicely. There is a decent amount of adjustments from the pipes, but very little from the hangers. Took a bit of fiddling, but nothing major. It clamps together, but seals well. (it includes connecting pipes and Thermotec heat shields)
But her voice. It's like that moment when Susan Boyle came up on stage, you cringe and then she opens her mouth, and you get ready for bats, chicken's and breakfast to come shooting out in some gnarly oral explosion... instead, a melodious tone, like a greek Goddess clearing her voice. The Corsa is like that. You expect it to be a dumb corn pickin' jock, when in reality, it has a Harvard style SAT score.
It really does sound good. I actually think it is the best sounding exhaust under 5000 rpm that I've ever heard. I included a bunch of video of driving around shifting at 3500-4000 rpm. It sounds like someone slapped a prancing pony right over that roundel. Cross plane V8 be damned, it makes noises like an italian. No joke, I had a guy in an 360 Spyder pull up next to me, and ask what brand of exhaust I had, and tell me that he wished his car sounded as good as mine.
When you start the car, from the inside of the car, it sounds stockish. On cold start it is a little bit louder and bassier, especially from the outside, but inside, it's hardly louder than stock. You can always easier converse over it. You can always easier hear the music over it. Most exhausts for the E9x M3 get bassy at 2000 rpm. Bizarrely, the Corsa doesn't. There is almost no additional bass over stock, which a lot of people will like. It definitely changes the voice of the S65 from 1000-5000 rpm, in a really good way. It's louder but not in an annoying way at all, it makes a really nice smooth exotic tone.
I remember eating at this little trattoria in Italy and there was this server there. She was just a little on the larger side, but had a full bosom and a killer smile, one she wasn't afraid of using to her great advantage. She had one of those laughs that grabs you and makes you want to know whatever it was she was enjoying. Her voice was extremely fun and flirty, heavily accented but playful so you were forced to give her your undivided attention. She flashed her smile at all of the customers, but reserved a special look in her eye for me, something just a little different so I knew she was paying attention. Her long black hair and her smouldering eyes sparkled as she laughed me with, and while she wore the same smile with other customers, her eyes didn't twinkle nearly as much as when she came around to my little table.
Her laugh is how the Corsa sounds. It's playful and sexy, teasing you if you try to short shift and pursing it's lips with a disapproving head tilt, if you stay out of the throttle. Push the gas harder and let it rev a bit and you get that full bodied laugh, that forces an extravagant smile from those around. You are not the immature high schooler, who hacked off the mufflers from mom's Buick station wagon, you've arrived and you've carefully chosen your exotic toys. At the end of the day, you're just as loud, but world's less obnoxious.
That's the story under 5000 rpm. Over 5000rpm, the exhaust gets pretty much drowned out by the induction noise, as with all quiet exhausts with the windows up. (Akrapovic slip on, BMW perf, Eisenmann, etc) It still sounds glorious from outside the car.
It's tough to tell volumes from video cameras, since they are constantly adjusting the levels of recording, so you really don't get a good idea of how loud they are. The things to notice is how loud they are relative to other things. You'll notice that in the MXP video I shot, the outside the car shots at high RPMs, the exhaust completely drowns out everything else. In the Corsa shots, you can still hear some road noise, etc. It's a decent amount quieter.
All in all, this is a great exhaust. Sounds good, fits well, etc. It's just not that pretty. And, it's not very loud over 5000 rpm. If you want something so that people know you are coming from 3 blocks away, this is not your exhaust. If you want something refined and not a ton louder than stock, but with a much more melodious and exotic tone, pick this one!