I'm running the extended chassis so that I can run normal servos.
for my build:
Purchased from ebay:
Castle Sidewinder SCT & 3800kv motor $90 shipped
Jammin SCRT motor mount $18 shipped
battery box, rx box $5 shipped
I used the "bill me later" and got $20 back on my purchase, so basically I got the motor mount and battery box for free. I just paid it off this weekend so I don't incur any interest fees.
I'm going to use a flysky $35 radio and a cheap hitec metal servo $30. A couple of $20 turnigy 4000 mah hard case packs and I'm good to go.