I have a 85 TA with T-Tops. I work in a metal shop and have access to welders and all the metal I could ever want. I want to beef up my chassis, so what else could I do besides making my own SFC's, STB, and Wonderbar? What and where is the brace that only convertibles have? And finally how thick should each one be?

 

you could make tubular rear control arms and a panhard bar but the polyurethane bushings aren't cheap so it might just be worth it to buy the parts from a company since they come with poly bushings. if you want to get really creative you can make a tubular torque arm

 

You might want to consider beefing up some of the braces/brackets under the car... for example, the body bracket that the track bar (panhard rod) and track bar brace connect to, on the passenger side of the car. I'm sure that putting a thick panhard rod on the car must give some additional stress to that body bracket. You might want to strengthen the track bar brace, too... it's main purpose is to keep the body bracket from flexing.

Maybe you even want to kick around trying a rear shock brace, although, since the top of our rear shocks are connected anyway (by the floorpan), I doubt you'd see much of an improvement. Be careful with adding too much steel, you don't want to wind up with a 3 ton car.