Kevin,
For autox and short-track TT (POC STS) you should be fine with the Renegade seats and a basic harness setup.
Vandecar's email is
poorshanut@aol.com
Their site's contact page has little icons for mailto links - it's a little confusing as opposed to just printing the addresses IMHO
http://www.porscheclub.com/about/staff.shtml
Other way to go is to contact one of the official tech stations. Hergesheimer is one that I believe is somewhat in your vicinity.