I think I have a standard set of cats for a 370Z at home I will have a look later when I get home from work. If you wanted highflow cats you could try @Tarmac@TarmacSportz for some they will sort you right out.
Hi and welcome to the OC. My wife has a 350z vert. when she got hers it was her 1st sports car. She loves to hoon it about when the chance arises I can't advise about the clutch, but I am sure someone will be along soon to advise you.
Trax is a massive event on its own without adding japfest to it. So as above deffer to next year would be the best route to take, i think would be best.