caged

c'mon, don't we all laugh at yuppies?

the 4.0L has lots of power, it's when you add big tires that it gets sluggish.
if you regear, you won't need all that add on fake crap like tb spacers and cold air intakes. waste of money.

either regear, it's money well spent, or live with it. don't throw your money into a losing battle.
once you regear, then do a stroker with port and polish.

joeksjeep

id say best thing is free up your exhasut with a good straight through muffler, and make and intake with a big cone filter and bore out your stock throttly body. You dont have to send it out just bore out your tb all around your BF valve. Thats what i did i have the underside of the Bf valve almost as big as the diameter on the intake manifold. The top is less but i left a patch for the Bf when it sits at idle so you dont screw with your IAC . It also makes a venturi and speeds up your air going into the intake

JeepCoMJ

you need to remember that our 4.0's NEED back-pressure. so, a 2.5" ID exhaust is really about the biggest you should go.

I agree about a better flowing muffler and also catalytic converter, but be wary and very picky in your selections.

boring in a perfect circle is hard if you don't have the proper machinists tools.

Wrecked

Why do you have to be so picky about a muffler and cat?

JeepCoMJ

because if you don't actually know what you're looking for when it comes to back-pressure, and you go with some insanely hi-flow cat or muffler, you lose all back-pressure or at least most.

end result, engine will actually lose power. it's all about maximizing efficiency.

BumsModified98xj

i put a magnaflow muffler on mine and i love it, and the sound is what a true i6 should sound like

crdude

I have no muffler.... or an exhaust behind the cat for that matter.. my friends say it sounds like a riced out BMW. lol

salad

BumsModified98xj

Its aslo backed up by BANKS revolver header!

BumsModified98xj

Im a verry happy man tonight as today I received a package in the mail containing my obd2 bluetooth scan tool.i can read and clear codes & monitor it all from my smartphone (Galaxy Note2!) For only $18 shipped to my door. but the best part about it is I can watch what is going on in the engine real time like timing advance and MPG's to engine load and intake pressure, etc.I had stepped out to do some erens and put it to a test befor I jumped on th E-way my intake temps where at 58.6°f when I was 1/2 hour into my trip and got off my exit my intake temps droped to 30.2°f! Wow me & my 4.0 where really happy all that ICE COLD air charge! My homemade CAI really works now all I really have to do is fabricate a heat shield/cold air box.