biggest horsepower gain from exhaust for an 08 bmw m5?

my m5 is unbelievable. the only thing though is that i want a better sound from that thunderous v10. i was wondering if anyone could give me any ideas on any exhaust sytems with big horsepower boost for e60 m5.

thnks

2 Responses to “biggest horsepower gain from exhaust for an 08 bmw m5?”

  1. John C on June 17th, 2010 9:13 pm

    As this is the question you hear from almost all wannabes; I’ll give you the wannabe answer.

    Exhaust is exhaust. Any reputable company that has developed a high performance system will probably provide the best results. Any differences in gains will be negligible.

  2. nj973man on June 17th, 2010 9:13 pm

    The M5 is just about perfect. I assume you’re talking about the sound inside the car? Have you ever heard it from outside while someone else is driving, and heard them take off down the road? It sounds incredible.
    You’ll be wasting your money changing the exhaust for no real reason and no real gain in HP.