I have a Thunder Tiger Trainer 40 that I have been flying for several years. I started with a TT GP40 and later picked up a TT GP42 cheap so I put that on it. The GP42 has more than adequate power and is relatively light-weight. I have two (2) TT Pro46's and this things are really impressive for the money. It is not too much power for the trainer but the extra power and little bit of extra weight will not be any advantage. I recommend getting the GP42 for this particular trainer because it is such a great match.