I think the 75 would be to much for a the model. I dont know about the Extra, but I had the Sukoi with a 70 four stoke on it. It had more than enough power. I think the 70 four stroke is about the same power as a 50 two stroke. So a 60 should be more than enough prower. Like some of the guys have been saying, these are not a good 3d birds. My Sukoi flew alright, but it was nothing special. Watch the fuse, theres not alot of plywood used, at least not on the Sukoi. Mine snapped in half at the at the back of the canope.