I was going through my old catalogs, making some room for newer ones, and found a Chassis Shop catalog I had from a few years back. I went to their website, and find that they have a new turbo section now. Lots of goodies for designing your own system, like flanges, wastegates, popoff valves, etc, not to mention the turbos themselves. Here's a link. Enjoy.

Chassis Shop (http://www.chassisshop.com/pdf/turbo.pdf)