RE: Too much power?
The only too much power I can think of is weight. More power = larger engine, larger engine = more weight. Mostly just calls for relocation of batteries, Rx and servos. Putting a hemi in a cigar box is too much. I regularly put a larger engine than the specs call for because I fly from a field that is 5,000 ft. ASL. Example a .60 in a Kadet Senior. Calls for some flight pak shifting but it works. I always plan on the largest engine I can install without totally unbalancing the model or exceeding the safety of the design. I prefer to fly on the wings rather than the prop so I try not to tear them off.