50 HP gain

Yeah that coffee can exhaust thing has been around for some time. Type R stickers add a further 20hp and NOS stickers add 100hp. How about some blue blinker fluid and dual roller muffler bearings for another 30hp?
If you want a REAL 50hp (and 40lbft) gain from your 4.0, copy the performance mods that I've done to mine:

http://www.jeep4.0performance.4mg.com

ROFLMAO!!!!!!!!!!!! Somebody help me find my teeth...I spit 'em out when I checked out that site...But seriously...for that trick to work properly, you have to add a second, non-functional can to the other side to counter the vortex imbalance...dang i'm getting old. They make DUAL Roller muffler bearings now???? But i got the juice.. :jester: .Synthetic blinker fluid.

Funniest thing I've seen in a while.... arty:

That was great especially the sound effects.