I enjoy my Formosa very much. I'm using Tanic and Kokam 1500mAh 3S1P packs, a CC Phoenix 25 ESC, and a 2025 4200 Himax motor. I'm using the GWS 400C gearbox with an H (5.28:1) gear ratio. This is about the same as a 350C geabox with the C ratio. I swing 10x6 or 11x7 props on it. The 10x6 is good for about 15 minutes flying time with excellent performance. The stock 350C motor is a lot of fun with a 3S lipo battery, but the brushes are destroyed at the end of one 15 minute flight. I run a speed 400 motor on a GWS PT-17 bipe on the 400C gearbox with an E (3.40:1) ratio. The speed 400 motor holds up quite well with the lipos. My complete drive system for the Formosa is available from
www.e-flightline.com. You may want to reinforce the fuselage for the brushless system. Here is a pictue of mine after the 21st flight. Oh - I add a stick from front to back of the fuselage over the battery to ensure that the battery pack is still in the fuselage at the end of the flight.