i was about to buy the SAITO 100 for the u can do as my next plane.. but looking at the money i have i have decided to go for the MAGNUM 91 as my FIRST FOUR STROKES... the reason why is they are lighter than TT engine and a tad heavier than SAITO.. and they have GREAT service. and i'm sure this combo would give it unlimited vertical! (i hope so!) so if you are running low on money get a cheap 4 strokes like the MAGNUM 91. hope this helps, and come over to the U CAN DO 46 thread.. you will get a lot of questions answered there