I've got a Tower 60 in mine and it flies fine. It will do Basic IMAC aerobatics, but it is limited on vertical. If you are just looking for a good all-around flier, then the OS .61FX will be okay. The ST .75 will give you a little more power if you'd like. Personally, I like OS engines, but for the price, I'd probably get a Tower .75. I've had good results with their 60 size engines (I've got 2), and I have a 75 in the box waiting for a home.


Kerry