Old GPM external "turbo", I think. Decent thing from what I hear, but doesn't compare to the newer Nellies or Spiders. If you can figure out for sure how to install it, I'd give it a try, otherwise I'd leave it be. The new Fairchild 8858 FETs are nothing to be sniffed at, and upgrading FETs is a very well documented process.
Your front end looks severely toed-in but otherwise I'd say you did a good job putting it back together. And a working MR01 for $20, I'm jealous.