DAVE
I have a YS-91 on mine and I couldn't be happier!! 16X4w APC using 20/20 fuel. I almost went with a YS-120 but glad I didn't I couldn't imagine more power than what I have already. Balancing this airplane was no issue using the 91 no extra weight was added. However I did mount the fuel tank on the c.g. and I do notice my trim does not change as I burn fuel-- I will do this to all my planes in the future. This is one great combo! you'll love it. GOOD LUCK.

AJT ;^)