Which is the best fitting exhaust
 

I am looking at buying an aftermarket performance exhaust system.
Has anyone had experience with any of the following....Borla.......B&B......how good do they fit and is there a HP gain?

I can only speak to the one I bought which is a Dansk and it fits perfect. It does raise interior cabin resonance especially with the top up in the low RPM range, the quality is excellent. As far as HP I think most of it is psychological but when you reach the top RPM's the sound is awesome.

Best bet is the factory muffler with the bypass pipe mod. Factory quality with great sound.

Deluboz stuff has been excellent fit for me and fabspeed.

Go over to www.caymanclub.net and do a search on Borla, Fabspeed, B&B, Capristo, APR, etc. A boatload of articles there, with special emphasis on the new Borla. And just about anything that fits a Cayman or Cayman S fits a Boxster or Boxster S.