For a full complete turbo swap is alot longer than 3-5 hrs. For someone experienced probably 20-25 hrs, no experience 30-40 hrs.P800 or Alpha 9 for best response. GT800 for coolness
Check this thread for more info for dyno comparison on turbo kits http://www.nagtroc.o...overlay-thread/
on a serious note, if you had start off fresh..like stock GT-R, I would go for GT800, but if you already have bits and pieces modded in the engine..like suction pipes, downpipes, actuators, then just go for P800 or Alpha 9 as those are reusable.
time to drop engine is different shop to shop. roughly 3-5hrs