I had a pettit downpipe installed over the holidays. You can really hear your turbos spool up now and can tell a difference in the sound and low end power!!

 

Congrats!

I'd have to say the downpipe was one of the best upgrades I did. The only other one that made the most noticeable performance change of my car besides my downpipe was the Eibach Springs.

Not really a "go fast" upgrade, but it made the handling so much better than the stock springs. And the lower look didn't hurt either.