There are a ton of excellent shops...here are some I have dealt with...I have gotten a lot of stuff from Quadratec...most excellent customer service...JC Whitney...very good also...if you are buying engine/performance stuff...nobody beats Hesco for the quality of service...excellent support too...Rosser Think Jeep...very good place...Randy's Ring&pinion..thumbs up...Tom Wood's custom driveshafts, ditto...ok i'm getting off my soapbox now...
The Best place to buy XJ stuff is through RJ at www.authorizedvehicle4x4.com I have gotten the best prices over all the others and he is easy to talk to. He tells you if it will work or not and has helped me build my XJ from the ground up! Thanks RJ!!! Megan