HPI makes some pretty good stuff. They certainly arent crappy like OBX but are closer to a company like Trust/Greddy. They may not have a huge research facility to make perfect intercooler designs like HKS, but they are high quality, track tested.
They also make a crapload of other parts than just intercoolers. They make suspension componants, oil coolers, carbon fiber pieces(like doors and spoilers), exhaust manifolds, acrylic windows and turbo lines, thats what I can remember off the top of my head. I once thought that they were just a small no name company but after seeing some of there parts and ads (in Japanese mags) I think differently.
Just check out there website for all their products...
http://www.hpi.co.jp