I did a 2 front 2.5 back and did not need to change brake lines or anything else. They were tight, and they were worn, so I upgraded to longer stainless steel lines, but my mechanic said it was not necessary. I was starting to get some cracking in the lines so replacement made sense either way. Also, at 2.5 you don't need to mess with the driveshaft or the steering stabilizer. You may want to get the steering box reinforcement kit from ORD or a similar shop if you are going to offroad it, the steering box can be a weak link I'm told.