I just installed a top hat lined 4.6 in my '04 and a rear 1/2 frame N/E truck. Love my discoWell, like all great Land Rover improvements one issues goes away and a few others fill the void. Remember, the 4.6 is just a stroked 4.0. Nice thing about the Discos is the wealth of information out there and the trucks are old enough that they are much easier to work on. Download the RAVE manual find some good vendors and start tinkering. I would not trade the experience for anything.