Hitec HS-81 on the throttle to save weight, HS-225BB will be fine for elevator & ailerons.
To get more power (RPMs) put a .40 FP carburetor on your .25FP it will fit I have done this. The bore in the barrel is larger.
Also take the baffle out of the muffler and then drill/ream/dremel out the taper in the exhaust exit.
To go completely BONKERS install the O.S..25FX or O.S..32SX