with a price difference of a few hundred bucks in the scheme of things i really dont think it should be an issue to someone doing and upgrade for the 250+kw range. The amount of money you have to spend doing with either option with all the supporting mods, ecu, injectors, pump, fpr -if required, z32 , clutch etc makes the $300 or so quite a small figure. I'm going to go the hks route as i fugure if i am spending all that money what is a few extra hundred bucks, and you get a brand new HKS turbo with brand new braided lines and new fittings etc. Not to mention the testing that would go into the HKS unit. That said, I am sure the gcg units are equally as capable - I just think if you r gonna spend 5k getting to 250kw from 200 the extra price isn't really an issue.