If you do re-shim make sure to get a re-shim tool. Bleed the lifters while you're in there, don't mix up the shims or the ninja angels of nissan gods will literally haunt you forever and your car will not right also. But everything else has pretty much been covered in this thread. Swapping lifters is super easy, just pop the cams out of the way and you're in business. Just make sure to tie off the timing chain tight so you don't have to go fishing for it at he bottom of the timing cover. This will make a simple lifter swap a job from hell.
