So I'm planning on buying a set of these Sparco's (http://www.sparcousa.com/product/r505) to fit in my car, but Sparco does not make vehicle specific rails. So I guess the question is, has anyone had to make a custom rail or is it just the simple matter of modifying the 86 rails to bolt to the seats?

Buddy club, , bride, nagisa, and sparco make rails for them.

Also this thread which is about 10 posts below yours
viewtopic.php?f=9&t=1236

Yeah but who bothers to look. Thanks for the link.

Almost done with the how to, I keep adding more pics and stuff to it lol.