theres lots of places to buy stuff here are some links i know:

www.lancershop.com
www.vividracing.com
www.gruppe-s.com
www.boostsolutionsinc.net
www.machv.com
www.vishnutuning.com
www.drcimports.net
www.rmrproducts.com
www.worksrally.com

some are expensive but have enough info to let u know whats out there, have fun.