The Webra 50. Like Bob said it comes out wicked nose heavy even with a 40. plan on installing battery and receiver as far back as possible.
One note when installing the verticl fins, make sure you leave the fuselage hatch off so that you can distinguish the top from bottom. Somebody I know left it on and glued the fins upside down
That guy noticed the goof about 15miutes into 30 minute epoxy and got lucky.