The cage would need a number of additional bars to have it meet Rally America rules unless it was a FIA approved kit... Plus...Spill kit, RA approved seats, intercom, map light, Tow hooks, skid plate and fire extinguishers... Besides that, you can just show up at a rally and do the school and you're going racing. Not all that P.C.A junk. Also, rally drivers are WAY cooler...
Not that I would know...
http://www.rally-america.com/info/2008_Rollcage.pdf