The 4-star is a terriffic plane. I've done the 40 and the 60 and converted the 60 to a twin. There are two changes that I made to both of mine. First mount the engine as low as you can on the firewall and still have prop clearance. This gets the carb closer to the fuel tank centerline for easier tuning. You will probably have to trim the cowl cheek for muffler clearance. (presuming you are running a two stroke). Second, add some triangle stock to the landing gear mount. Granted my landings aren't the prettiest but I managed to skim the gear off of both of mine.

Madmen at large...they're everywhere!