Here is my setup for the p-51 Mustang combat:

Plane: http://www.towerhobbies.com/products/... Andy's Hobby Towne has this for $89.00

Motor: http://hobbycity.com/hobbyking/store/...) FOR a FAST PLANE
OR
http://hobbycity.com/hobbyking/store/...) FOR a Medium Speed Plane

Speed Controller: http://hobbycity.com/hobbyking/store/... You will need this minimum, please don't use the 30 amp one as you'll be pushing some amps at WOT.

Prop: APC 8x6(If you go with the FAST MOTOR) or 8x7 (if you go with the Medium Speed Motor) you can pick up these Hobby City Props, as they work pretty good too:
http://hobbycity.com/hobbyking/store/...
http://hobbycity.com/hobbyking/store/...
Please balance the props as you will be spinning them pretty fast.

Batteries need to be atleast 3000Mah 3s, the zippys work well:
http://hobbycity.com/hobbyking/store/... I would get atleast 2 packs so you can finnaly more than once.

Finally any good Micro Servo will work well, I have a prefrence for the Hs-85MG micros from hitec, but these work well too:
http://hobbycity.com/hobbyking/store/... You will need 2 of these servos for the electric conversion.

Lastly, some nylon spacers and 2-1/2 inch 6-32 Machine screws w/locknuts to make your firewall mount.

I checked hobbypartz.com but they dont' have a lot of the items in stock so I reccomend picking them from hobbycity, all the gear should be around under 130.00 shipped.