I Have A Full Dynomax Cat-back On A 2002 Formula With A Six Speed And I Was Just Wondering About How Much Power Do U Think That I Gained From That? And Wats The Best Cat-back And Exhaust Out There By The Performance Numbers.

 

You may have picked up 10 or so... at the most....Get some long tubes and a lid and filter..

 

There are quite a few catback systems, as well as header options, and it all depends on what noise level you can take as well as what mods you plan on doing. I agree most catbacks will add 5-15 horsepower, but tuning the car for the additional flow can also help out. Headers and a high-flow Y or off-road Y will also help out, but don't forget to concentrate on the intake side as well (lid, high-flow filter and cold air).

Check this thread as well: https://ls1tech.com/forums/generation-iii-external-engine/140408-exhaust-reviews-sound-clips-ls1sounds-com.html

Derek