Outlaw or DD
well. as i see it its a light weight fun fly with the 32 being perfect, but i've also seen americans have a habbit of putting big engines in funflys. in this case a 45 is big, heavy ect, but it's not OTT, the airframe will take it, but it's right at the limit. i have a 36 and pipe on mine and i can go from 120-130mph level flight into a blur spin that makes it stop. i was shocked that such a frame can take it. maybe replace the 1/4x1/4 balsa spars with spruce. but as long as you don't do a full power blender first flight it should be ok. If the engine fits in the cut out at the front, go with it. if you got spare cash, get a OS 32 or sommit.
going with a funfly prop, ie 11x4 or something will stop you getting too fast, but you'll have pleanty of grunt for spins.
one tip, build the rudder and throttle servos into the ribs ( horns facing inwards ) this saves alot of space and hassle inside and will allow more movement of the batt and rudder. my radio bay is also quite a bit longer than on the plan and i have a flat 4 cell pack at the very rear, balances perfect.