Sponsorship - I guess start off with the official/big distributors/dealers of Honda tuning parts like J's Racing [JDMConcept?], Buddyclub, Spoon, etc see if they want to jump in? Then after that

Competitors - Mix of pros/workshops and privateers with some sort of regulations like say N1/N2 for example? Which should keep cost and competition controlled and within reach of most? Or Perhaps something like GT300/GT500 that allows two classes?