You'll also have to have your wastegate setup with the right springs so you dont lose that extra boost but that shouldn't be a problem some of them come with a variety of springs. But you should definitely go with an intercooler, as far as the hiding of the intercooler its possible with some modifying you could use a fender mounted one from a mistu or something. Even with the smaller fender mounted intercoolers you can safely boost up to 14psi. Look on Ebay for a intercooler you'll see what I mean.

Ls@22psi