have to admit I kinda forget that you have all that Audi stuff going on, which might make the rear a little more complicated
Also, I definitely don't have a diffinitive answer of "buy this at this place" since I had already started down the Porsche parts path when building based on the stock tub, I just wish I had done it differently from the start.
That said, I would look into a front suspension clip kinda thing for a SuperLate or Tour car (like SouthWest/Northwest/Midwest Tour).
Howe Racing has tons-o-stuff for NASCAR and is a popular source. Here is a front susp example and links at the bottom for others. You would just use a simple GM drop spindle and a hub/rotor/caliper setup of some sort (like Wilwood)
http://www.howeracing.com/Chassis/Index-Front-M.htmjust have to be sure whatever hub you use, they typically have that long "snout"/bearing cover, so be sure your wheels will fit over it.
You may or may not be able to adapt a stock rack to work - you would have to determine pivot locations of the arms and see if you can set the rack to minimize bump steer. Otherwise, they probably have a rack that works. Maybe even use a power steering rack (hmmmmm!!)
you can start at the home section of Howe and go thru all the links for hours of enjoyment
http://www.howeracing.com/As for the rear, you can get hub assemblies from Baja sources that you could build into your own upright. As to whether you can specifically get a 5on5 pattern I didn't check into, but seems plausible.
Then just get a custom set of axles that are the right length with the correct CVs at each end to mate to whatever hub assy you got and the Audi trans.