I had borla's stainless headers on my 4.0 TJ and certainly felt an improvement. My stocker had a crack in it so it was a need more than a want. It was not cheap, but it was a quality piece. Coupled with a borla cat-back and a random technologies performance cat, it had a great sound and 100% stainless, so I knew I'd never have to replace. All of borla's stuff has a million mile warranty I think. I have also heard good things about thorley headers, but I have no experience with them.
Tony-04 Limited HO
, DkKhaki w/tan leather int. All LED lighting, 5000k Xtreme HID projs. (deambered)&fogs w/CCFL rings, tinted tails&3rd LED brake lt, fnt glass tinted to match, shawty antenna, 6 Polk speakers, K&N FIPK, FR 70mm TB, TCM#10 snip, Flashpaq'ed on 91 tune, Bilstien HD's, Addcos, polished 20" SRT reps, Hankook Ventus Evos (255-45), Weathertech mats, EBC USR rotors, EBC Greenstuff pads, Magnaflow muffler, RB1 Nav w/iPod kit, de-badged, roof rack delete.
09 Liberty KK
Rocky Mountain Edition. Added Mopar Remote Start kit, Weathertech Mats, K&N drop-in.
: 99 TJ Sport, 98 XJ Sport, 06 WK Laredo