On thewizard's car we welded a 1x10" strip of 1/8" thick steel plate across the bottom of the crossmember near the rear mount, drilled holes in it, welded nuts over the holes. Drilled the radiator support, and bolted a piece of 3/16" aluminum to the strip in the back and to the radiator support. We have extra aluminum 3/16" sheet and crossmembers lying around too, if you're interested in throwing down some change for a skidplate setup
The aluminum we (I) thought we could bend with some mechanical leverage, but nothing we had available to us at the time could get the material to give even fractions of an inch. We decided to just bolt it up... and well, it worked for us. The plate has a nice curvature to it too, which in a way is better than just a flat skidplate.
Posting this up for Serious b13... check out your old car man! This was taken down at the DC rallyx this past weekend. Thewizard is driving.