Had one (and then sold it)... had a Webra 40 speed on there. Needless to say it was incredibly overpowered. And the engine, altough light for a 40 size, was probably too heavy for this plane. I'd stick something like an OS32 SX or Webra 32/35 on there for a lot of fun. Keep it light...

it'll fly with the 45, just keep the speed up on landing. you might consider taller gear for the size props you'll need.