If you go to the sealed motokhana style event off pascoe st you dont need to worry about a helmet as the msnz rules its run by you dont need one.
But if you go to one of the Auto X's you will need a helmet. They have thick cotton overalls you can use at the event if you dont have any overalls or the race type. Its always better to bring your own thou! As for a helmet if I am there you could use my Stilo one during the event as cars are numbered & spaced so you can run the rex & use mine. I always use a hood inside my helmet so you dont have to worry about cooties!
Check out the Nelson Car club site. www.nelsoncarclub.co.nz
Theres a Race your Road car event coming in Orion st, off Pascoe st 12th April. Quite a few events coming this year. Im plannin on havin rex ready for June gravel events, maybe Sandy bay sealed event in may if i am lucky!