I have just installed the rear strut bar for a B13 into my B12 today. I had to do a little metal cutting, to get the mount plate to sit flat. I got the bar from a group buy on the Sr20de Forum from Active Tuning. Checkout the pics.
If you look at the photo below of the strut tower mount you will see the metal that go across behind the front screw. It was sticking up and would not allow the strut bar to sit flat. The strut bar fits perfect. Nice work on the rear strut bar.