You wont run lean the MAP will read on how much air passes through it unless you have a vac leak. Getting the larger TB will just be a waste w/o cams and a tune cause your motor can only move so much air. When you buy the aftermarket IM your buying the name mostly and runner length and some other things. If you really want to make some power and use the IM for where it will perform the best at get a turbo set up and tune it.