Dave Brown mounts, I also tried 2 different engines on my 4*40. The two mounts had the same mounting pattern at the firewall so it was a bolt in swap. That was nice.
I started with a Sig Senior with lots of flight time on it , then went to the 4*. Even with the slow engine in it, the first few flights were knee knockers. It responded SO much quicker to all inputs. Keep the throttle back for those first few flights. My plane wasn't much fun with the slow engine, put in a ST G51, now a lot of fun. Still flys slow with the throttle pulled back.
I tinted the canopy black, the topside color is yellow. That black canopy really helped with orientation while flying.
Have fun, Mike