Thanks for the info joe.
The camber and toe plates finally shipped. For future reference, the perches DO fit the 318ti. I will be documenting the install in my autocross build thread with tons of pictures:
Riddleyo's Autocross 318ti I looked at the Ground Control perches as well, but the IE ones were much much cheaper. And you can use your own source for springs. I will be using Eibach 2.25" x 5" springs which are pretty plentiful on ebay used. You are right, H&R sport/race are WAY too soft for autocross use. If you want to track the car, you gotta go stiffer.