Make sure to check out the Supercup exhaust, it would be the way to go without being crazy loud like muffler bypass pipes. So it will still be very aggressive and loud, but not as loud as the stragith pipes. Let me know if you have any questions and PM if your interested and I will make you a nice member deal on a set.
Thanks,

996 Supercup: http://www.youtube.com/watch?v=2uNw_8zZViA

 

Why bother messing up a perfectly tuned car with cheap/loud exhaust?