you can make the S just as good/fast as an R swap, especially if you find a 2005 S engine. Only thing you miss out on is the LSD; and the 4.7 final drive (if you don't find an '05 type-S which have the 4.7 fd).
The question you should be asking yourself is 'do I want LSD?'. If you want LSD, get the R, if not, save some $$ and go with the S. Not only do you need to getta Kpro, but also a bolt-in kit, a good header, & PnP wire harness, most of which you can get faster because of the money you'd save on going with the S swap, depending on how much $$$ you have saved up for the overall swap..