Wowbagger,

The YS 63 will swing the same size props at similar RPM than the Satio 91!!, (its all in the super charging). If you are talking of spending that kind of money, then go for the YS. But I still think that your airframe is too heavy though. If you can drop 1/2 to 1 lbs of it, the motor setup you have with the 12 1/4 x 3 3/4 WILL be fine. The extream lite with your running gear should be fine and will cost less than a new engine!... One thing to note though, I have found all my funfly aeroplanes with a 2 stroke to be noisy. I found that the motor is amplified, by the wing, to what is in effect a big drum. This is one of the resoans for going 4 stroke.

As for the Ripmax display team, my understanding is the put irvine carbs on them.

Cheers

Kris