[Chambers]

I would stay away from a lightweight under drive pulley unless your crank has been balanced for it. Without a dampener on it you will destroy your bearings and fry your engine.

I would say to hop up a NA, engine wise, first exhaust and intake. I would favor a 2.5" ID cat back, test pipe or high flow cat, and some custom headers. You can buy headers but I have yet to see one that is tuned for the firing order in a Supra. As for intake, you can get a dry filter, and do a little fabbing with some tubing to clean up the flow path to the intake.

If you plan to dig into the engine, you can do a port and polish and put some more aggressive cams in, get your rotating assembly balanced and blueprinted.

Then no matter what you do, even if its nothing you can get a MAFT Pro, it will allow you to tune your engine, so you can do almost anything and then tune the MAFT Pro to run your engine correctly.

Other than engine upgrades, I would suggest the common, light weight fly wheel, upgraded clutch, one piece drive shaft, and the changing of all the fluids in everything.

Hope this helps, good luck.