I used a 91 fs in mine for a long time ,It's a good combo and ran fine inverted After I got used to the plane and began hovering it, I wanted more power so I installed a YS110FZ ,and wow! what a difference, It will hover at 1/3 rd throttle and the 110 fit in he same mount as the 91 ...an easy swap....I love this plane....when you install the tank I would use a seamless tank if you plan on upgrading the motor to a pumped engine like the YS110 at a later date ...As far as the landing gear I just cut a small hatch in the top of the fuse under the canopy and it made the mod's very easy to get at the landing gear mount ...after I beefed it up, I just recovered the small hatch ,smoked the canopy ,and have had no problem's just fun.....JW