try asking questions on their forum on
www.hyundaiaftermarket.com
you can get the kit from the shop at
www.hyundaiperformance.com
they put for off road use only because it is prolly not legal, and they dont want to be held liable for it. you wont need a header, because you get a manifold with the kit. it would be a good idea to get a free-er flowing exhaust, but it is not required. they use a unichip for fuel management though, so you will need to find a unichip dealer that can tune one to get your car running right.