If its tuned properly you should be fine there, although with higher boost and E85 you have to worry aboyut NOX readings being high. You can always take a junk CAT and split it in half, then hollow it out, and weld it back together around the "test" pipe so as to give the appearance of having a functioning CAT on the car.
Oh, and way better platform choice this time. I very much approve. Are you going to go for more of a Rally look or Road course look with it? Either way, me very much likey likey the little Subie.
Or