I had a GMS .47 in my SU and it did okay. .. but I wanted more thrust. I put the saito .72 in on 15% fuel, and what a difference it made! Not unlimited vertical, but very good vertical and it was very thrusty. Snaps had great authority after putting the .72 in. I have a .82 in a box now, and you guys have me thinking! Even better, I'm sure.