Hi Brett,
When I was in Hawaii a year and a half ago there didn't seem to be much happening in the way of motor sport. I think the track on Oahu had been closed for some time. On the big island of Hawaii there was still a little bit happening.
I dont know about suppliers but the quick search I did while in Honolulu didn't turn up anything very interesting. Great spot for a swim though and err the missus will enjoy the shops
cheers
Paul