[greentrbo95gst]

It depends what you are looking for, you can have slightly louder car with mild performance gains, much louder car with mild performance gains, stupid sounding car with no performance gains. I won't name the names, but most of you know the brands associated with each option. At the end of the day, you should know that you are not buying an exhaust for performance reasons in the M5. BMW engineers did a very good job at maximizing the performance of the stock exhaust with enough airflow to eliminate any possible doubts about upgrading. I ran 11.3 with OEM exhaust and tires so hopefully that tells you something.