There are quite a few options other than DPI.
All the lower control arms are an inferior design as far as I am concerned, some one needs to make an A-arm style LCA.
You can get braces from DeloreanGo or DPI though that triangulate the LCAs.
Listed by cost:
Factory Boxed and re-enforced - DeloreanGo or Clint Wolff (Clint does great work)
Byrne Heninger heavy duty steel - NLA, may find some used?
Stainless - DPI
Billet Aluminum - DMCMW