I'm not even going to say anything about the 'power plate' because I'll end up in trouble. But believe what you wish.
First and most importantly would be a ScanMaster! The one concern you should have is if the car is ALREADY running right. I wish I had a scantool when I first aquired my car, because I knew it didnt feel as strong as it should, and I would have figured the problems out much sooner then I did.
Once you have a scantool, accurate aftermarket boost gauge, and maybe a Casper's knock gauge (for instant responce), then you can start tweaking and 'modding'. Good instrumentation is important with these cars. These engines are fickle and liked to be tuned just right.
Go for the adjustable fuel pressure regulator, the Racetronix pump & hotwire kit first. Proper fueling is a must. Hotwire kit and pump seem scarey first looking at it. My first thoughts were "Oh my God, wiring and dropping the fuel tank!!!" It's a freakin breeze! I'd do it again just for something to do, its so simple.
Another thing is, be sure to take care of any preventative maintence first!! Spend money on keeping the car safe, before making it fast. Like me? I still havent done some things, like replace my old high-mile U-joints, balance the shaft and install my safety loop while I'm at it, take care of my noisey camshaft sensor that sounds like its falling apart, along with a few other things. Making sure everything is in good running condition will help prevent breaking stuff.
I'm still pretty new to the TR owners guild, but I'm learning quickly. These are just some of the most important things that I learned early on. Have fun. You own one of the most respected cars on the street. A dying breed. My car can be a pain in the ass, but I still love it. Wouldnt give it up for the world.