Depends.......If you want to go racing, the cheapest way is Spec E30...period. Spec E36 will cost at least twice as much to build. You can build the E30 to run ITA, ITS, Spec E30, M Prepared, K Prepared, PBOC, and even vintage. The E30 is the most versatile chassis you can have. There is a wealth of knowledge about both chassis as far as suspension is concerned. Good luck, Chuck