Okay let my info be spread over here on NICO. THERE ARE MANY... MANY MANY MANY MANY MANY companies who have parts for the Q's..... but they're ALL over seas. I have Japanese Mags and i can tell you... the Q's are the most dominating cars in these mags. So far i've never ran into any SC'd Q in the mags but plenty of Turbo'd Ones. Here are some of the many companies that I can think of by the top of my head that makes any kind of aftermarket products for Q's here in the US or Japan:
Stillen, JWT, Jet, Superchips (I don't know if they still do), Bomex, Mine's, JUN, Apexi, HKS, Junction Produce, Mythos, JIC, Eibach, Intrax, Tokico, Impul, WALD, TEIN, 5Zigen, Blitz, Brembo, Endless, MOMO, BRIDE (Full Reclinable), Zex, NOs, NX, Venom and Cusco.
Those are some of the companies that I can think that makes things for the Q. There ya go

Feel free to Add more companies to the list.