Saito 100 for sports, 125 for more grunt. Both fits into stock mount. Might be nose heavy - and you can move a servo back if you do not wish to add weight to the tail. Clearance with 16" inch prop ( for Saito 125 ) might be tight - so you might want to get 3 1/2" wheels.

I fly mine electrified with 1200 watts, AUW 7lbs. Quad flaps are a hoot.