does it really give as great of gains as they claim? 20-23 hp and 20 tq? also what else helps a lot? i have just a knn drop in and run 91 octane.......HELP!

 

You might get an extra 20hp at crank if your lucky but at the wheels Don't expect more then 5-10whp. Add some test pipes, a plenum, crank pulley and Light weight flywheel with a tune and most people would be satisfied.. If you want more power F/I is the way.

 

Stillen always gives higher numbers than anyone sees. You should see ~8-12whp from their exhaust.