Options? Well, you could always try this...
http://www.thirdgen.org/newdesign/te...nguprear.shtml
Here's one more regarding the amount of power a modified 10 bolt will hold up to.
http://www.ws6transam.org/10bolt.html
Don't mind the links, I also own an 89 Formula. They use 10 bolts as well, but with different mounting points. And don't get me wrong, I'm not defending the 10 bolt. I'm just posting this for those who are curious about its durability.