Getting into Racing....
Buy a Thunder Tiger PRO.40 for your engine ($70-$80?). Buy a Predator Quickee 500 ARF ($129?)). Both are available through Horizon Hobby or even your local hobby shop. Get yourself some PowerMaster 15% fuel. I assume you have a 4-8 channel radio? Glow ignitor? Starter? Misc. tools to assemble?
Join NMPRA. You can find more information at NMPRA.org
Randy