it will make a huge difference. i ran 4:1 in my old truck and it was way lower than stock.
the install was pretty easy for me. the transfer cases on yotas are nice and simple. although i think with the 4.7:1's you may need to grind the case out a little bit to clear the gears. also youneed to grind one of the shifter shafts. but that's not bad. it took me a weekend to do mine.
