rear coil-overs

[lightning bug]

Now that I may need to eliminate my torsion bars for my 915 install, I may be in the market for rear coilovers. Who makes 'em? Preferrably in North America. I checked out KAW....... just too far to ship ($$$$). I'm looking for ride height adjustability and a stiffer spring. I'll consider using Porsche parts too. Maybe there's a swap from a 944 or something. I'm going to research custom builds too. Any help is greatly appreciated. THANKS!!!!!!!!!!