Ok, so I have an 03' xterra 2 wheel drive and I am looking to convert it to a 4 wheel drive. Im pretty sure Im gonna have to change almost everything underneath-(rear end, transmission, front and rear drive axle, and interior gear console and maybe computer).. My question is has anybody done this and if so what am I looking at, as far as difficulty and if so what pointers and advice do you have for me. Also, can any year 4 wheel drive transmission bolt up to my 03' 2 wheel drive or do I need the same year.. If you have any input please feel free to respond.. Thanks