Rather than mounting 150hp to the nose of a trainer you might consider a different plane. Trainers are not designed for that kind of thing. You're not stretching your abilities that way, at least as much. When you're competent with a trainer move on. You'd be amazed at how much better a roll or hammerhead, split-S, etc looks with a plane that's aerobatic. (I still fly trainers from time to time for relaxation) Suggestions, Stiks (any of them), 4*40,60,120, Venture, Venus, 40 size pattern Arfs, etc, etc, etc. If you feel the need for speed, the Lanier Quickie ARF's will get you 100+ mph on a 40.