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-13 JKU Sahara
, Black. LED white fender lights and signals, retrofit Homelink GD opener, LED interior lighting, shorty antenna, weathertech liners, CF door handles, mirror covers, front grille, and gas filler. Rugged ridge phone mount and hood catches, dead pedal, ventshades, rampage windshield tie down and stops, solid stainless lugs, 20% front tint, sill guards, FMF spare delete kit, and your mom. ToDo list: LED tails, LED fogs and heads, and a bunch of other stuff.
15 Cherokee KL
Latitude Edition with cold weather package. Bone stock.
: 99 TJ Sport, 98 XJ Sport, 04 WJ Limited, 06 WK Laredo, 09 KK Liberty