Ok, please forgive the rant that I am about to make:
There seem to be a lot of decisions being made and minds being made up on this site using only video clips filmed by IPhones and mini-video cameras and their tiny little microphones, which are then played on laptops and PCs and tablets with their crappy, itty-bitty little speakers.
Now, don't get me wrong. I totally agree that the M Performance Exhaust for the 335i (and included with the 335iS package) sounds great. I know. I had one for almost 3 years. Loved the sound.
But I've read hundreds of comments on Bimmerpost how awful the 2015 AND 2016 M3s and M4s sounded. TERRIBLE. AWFUL. THE WORLD IS COMING TO AN END. BMW HAS LOST THEIR WAY. NO CAR HAS EVER SOUNDED WORSE IN THE HISTORY OF THE WORLD. BUY AN AUDI, A CORVETTE, A PORSCHE, A SKODA,ANYTHING INSTEAD OF AN M4!!!!
I drove a 2015 several times when I was car shopping, and agreed to an extent. I listened to all of the crappy little video clips, but wasn't convinced either way. The 2016 was supposedly better, but who could tell? They weren't available at dealerships when I was working on my order. The sound seemed to vary widely by who was recording, what equipment they were using, etc. And remember that the bass hertz on speakers is almost always of poor quality unless you use a subwoofer. But I had - - at least in my mind - - decided that I was going to need to spend $3-4,000 on an aftermarket exhaust as soon as I got my M3 back from Germany.
Then I picked up my 2016 M3 in Munich 3 weeks ago, and spent 8 days driving through Germany, the Czech Republic and Austria. Wow. It sounds NOTHING like the silly video clips played on cheap ass computer speakers. It's deep, throaty, has less rasp, and generally will scare the hell out of the neighbors and dogs and birds and sleeping babies as you roar by them at 5 in the morning.
Here's my caution: Don't judge until you hear it in person. The 2016s are much better, and if you set your M settings to keep the valves open, it sounds FABULOUS!!!!! It's not just as good as the 335iS, it sounds BETTER. Can you buy a louder aftermarket exhaust? I'm sure you can. I've had super loud exhausts (Borlas, Scorpions, Gorillas, AFE, Banks, etc.) on V-8 Mustangs, M3s, and my diesel pickups. But the stock 2016 exhaust sounds pretty darn good to my ears. One roared by me today on the highway (M3 in Mineral Gray) and it was awesome.
So until you come face to face with the 2016 beast, drive it, adjust it, live with it for a few days, don't make these snap judgments.
There, I'm finished now......
(this is bound to generate some really interesting responses, I'm sure....)