When I installed my SD. I removed the metal fan shroud. Bent the AC line just a bit for bit more clearance. I didn't have to bend the oil or trans sticks. Went ahead and flipped my sway bar for a bit more clearance and that's it. Some guys have to slightly bash in there firewall to give the upper O2 a bit more room but I didn't have this issue.

ZZP headers will flow better obviously but unless your going for all out power SD's would do the job for a fraction of the cost.