It is definitely a difference, but really I would say it only "feels" like an increase of 10-20hp, but it is a nice step up in performance, my speedo is WAY off right now
Back took me 1-2 nights (4-5 hours) each night. With a write up like this or if I had known exactly what I was doing I could've done it in one night easily.
Yeah but I didn't really find the front that difficult either, it was just the center link ball joint and the lower ball joints that were giving me problems, which if you are careful and know what you are doing you really do not need to remove them. I will write all of this up when I get around to doing the how to for the front, but yes the front is MUCH more complicated, and I will probably have at least 30 photos for that how to thread.
Oh and Independent 4x has sold multiple 5.38 gears for our front end but I am not sure of their availability as of now, I am pretty sure they are sold out as of now, but they are out there somewhere.