[Mk3FirstCar-Mike]

Twin-Turbo + 16 + First Car... I have a problem with this.
It's by no means a bad option, but that's going to deliver power from 3-500 horsepower, depending on how it's tuned. That's a lot of power for anybody to have in a street car.. and assuming you're like me.. You're going to drive like a f*cking maniac at random times. If you do end up getting a TT, make sure you know what you're doing while you're driving and don't speed in areas where you don't know the road well or in populated areas (not saying that I'm condoning speeding in any condition). You're also going to have to get bigger brake discs after you get so much horsepower, as the stock ones won't suffice. Drilled and slotted ones will also provide better cooling, which is, of course, good for braking.

Setting the car up for twin turbos would also be fairly expensive... and then there's finding a manifold for the build...
Things that would be required for a twin turbo set-up:
New Fuel System(Injectors, Fuel Pump, etc.)
Remapped A/F Ratio
Turbo Timer
Boost Controller
Twin Turbo Exhaust Manifold
Wider Exhaust
Wider Down Pipe
Wastegate
Intercooler
(I'm sure I'm forgetting some)

I would, however, recommend that if you get a Supra, to get a turbo model. They don't have a preposterous amount of power, but still a fairly good amount(About 230HP) and are easy to upgrade once you get some solid driving experience in.
In the mean-time, I suggest reading up, using various sources, about the cars that you're considering purchasing and the upgrades for them to ensure that they're readily available and not overly expensive.

Side note:
For God's-sake... please don't lower your car any more than 2" when you do get coilovers for it. It will, more-than-likely, completely ruin the way it handles. That is all. Have a nice day.