Russ, I think the Tri-5's are equal to the 1st Gen F-bodys - true classics, you just can't go wrong. One of the nice things about the car that you're looking at is that is has a full frame which you can work on separate from the car. It makes it a little easier to work with over a unibody car.
The most knowledgeable person I know when it comes to building and modifying Tri-5's is Brent (Ricochet). I'm sure he'll jump in and help with any questions that you may have.
Good luck!