When it comes to heat problems in the engine compartment I use 3 inch aluminum tape on the firewall and inside the cowl. Two or three layers works great as a heat barrier and the stuff is very light. If you'd like to know a little more about the Phoenix SU-31 check out the user reviews as I did a full review on the plane. My neighbor flys the extra with a Saito Golden Knight in it (.62 I think) and he loves it. We put a 13x4W prop on it yesterday and it flies great with it. Good luck with yours. If you'd like to look at another great deal check out the World Models CAP 232-46R. It's $119.00 and just an awesome ARF. I also reviewed that plane and have videos on Members Videos of it flying.