Help on long tube install on a 2002 WS-6
https://ls1tech.com/forums/showthread.php?t=139142
Quickest way I know is get some air tools, a lift, a grinder, and a cutter/sawzall
The way I would do it, get it on a lift, unhook the battery, take the plug wires and AIR off, loosen the manifold bolts, and have someone underneath cutting the stock Y pipe, when the y pipe is cut away, undo the o2 sensor connectors, and take the bolts completely out of the manifolds, and drop them to the guy underneath.
The guy underneath hands up the headers, the top guy bolts them up, hooks up the AIR/EGR and plug wires (he can also change the plugs if needed), once that's all done, he then goes down to help put in the Y pipe, and hook up the o2s (front and rear). then for the Borla, jack up the rear of the car (by the LCA mounts, so the rear hangs) then cut the stock cat back out, and install the Borla
Hopefully you're done in 4-5 hours, if you don't want to wait for the car to cool off, wear gloves and a long sleeve shirt
Depends on the car, I've done 2 sets now, on mine no grinding, on my buddies car I had to grind, but I didn't have to undo the steering shaft, or take the plugs out

