Originally Posted by Chris Peralta

For a pretty tight track I am gona guess that the 9901 might be a bit better but the 86 pipes always make pretty good power as well, but are meant to be more of a top end pipe. The best way to know what is best for you ad your driving style is to try them both back to back. There isn't anything anyone here can tell you that will be more valuable than that 30 minutes of testing.