In this issue of our Project ActiveTuning Version 3 (http://www.activetuning.com/pat/3/5), we install the new 3.5 headers from HotShot. We installed the "legal" version with the high-flow cat. As soon as they headers went on, we dyno'd the car, so take a look at the article to see the performance gain, and if it's worth your money:

http://www.activetuning.com/pat/3/5