I'd recommend the M Performance if you're OK with the cost. I like the Corsa and Eisenmann Sport also. The OEM exhaust mods are popular also although I've heard that the ACM mod drones a bit. I chose the M Perf because it just doesn't drone at all, has its own unique aggressive sound, looks awesome and is OEM...gotta love the laser etched ///M! I removed the inner tip black paint and painted the cans, just personal preference.
If you want a race exhaust, be willing to tolerate some drone. They tend to drone like a mofo starting out in first gear and under load.
Here's a pic of my M Perf, my buddy is wearing my old AA exhaust.
