My suggestions from a newb to a newb for a 12-second car:
0) Complete the spring cleaning found @
www.gnttype.org as soon as possible.
1) Get yourself a scanmaster. This is required to monitor several important functions under the hood, including Knock.
2) Fuel pressure gauge that can be monitored from the driver's seat while driving (mechanical hood mounted or electric in the car). This is required to assure proper fuel pump operation and 1:1 FP rise with boost in order to avoid lean conditions.
3) Aftermarket boost gauge. The stock boost gauge is unreliable and very imprecise, even if the one on the dash works correctly.
4) Adjustable fuel pressure regulator. This is required to properly set base fuel pressure for your modern PROM (chip).
5) A known-good fuel pump. There are a few different kinds that are widely used - Deatschwerks (sold by GNS Performance and others), Walbro 340 (255 lph available from Racetronix). This is required to be sure that enough fuel is making it to the motor.
7) A hotwire kit for the fuel pump. This is necessary to assure ample voltage to the fuel pump so it can supply enough fuel to the motor.
8) A way to increase and control boost. Increasing the boost is necessary to increase the power output from the motor. The cheapest way is to thread the rod on your wastegate actuator. In my opinion, the EASIEST way is to get some sort of manual boost controller (RJC Racing sells a very simple and economical one).
Items 1-7 are pretty much necessary for quality driving of ANY TR. Be sure that your motor is in good working order before starting to increase power.
Once you have the items above, then you have decisions to make about HOW you want to get to 12 seconds. Questions to ask yourself are:
Do you want to buy race gas? This gets expensive quickly. If you go this route, you will likely need two different chips - one for use at the track with your race gas, and one for use on the street with your 93 octane gas (or whatever's available in your area). The timing settings are different depending upon which fuel you will be using.
Do you want to use alcohol / methanol injection? These kits are a little expensive, but are tried and true. The alcohol allows for increased boost and timing by cooling the fuel mixture to quell the dreaded KNOCK. The alky injection can be used on the street or at the track, so no changing from chip to chip when you're at the track or on the street. The new chip you select will need to be burned for the alky injection.
Do you want to use E85? First question here is do you have this available anywhere convenient? It is my opinion that running E85 is the most economical way to increase performance as no injection kit is required to run it. Basically, you ensure that your fuel system can provide enough fuel to the motor (approx. 30% more E85 is required relative to gasoline), have an E85 chip to support the fuel, and that your fuel injectors are sufficient to deliver the fuel to the combustion chambers.
Once you determine what type of fuel you'd like to use, then you order the appropriate chip, supporting equipment for it (i.e. alky kit, or injectors, or whatever), and sneak up on the tune by fine tuning your timing, fueling, and boost. Find some folks in your area that know these cars (our board has members just about everywhere, so I'm sure there's one near you) to help you tune the car. Go slowly and do not accept ANY knock from your car. If you see knock, it is BAD; figure out why it is there and how to eliminate it. READ AND SEARCH ON THE BOARD - A LOT!! The more you know, the safer your tune will be.
Stock Turbo and Stock IC are plenty to get to mid 12's. Drag radials will help the most as they will allow your 60' time to shrink. Every 0.1 second improvement I have made in my 60' time has yielded an average 0.25 second improvement in my ET (sometimes a LOT more).
More experienced members will chime in and offer information that I have forgotten I'm sure.
These cars are a blast and you WILL have fun with one I'm sure. There is NO better source anywhere for information and help than turbobuick.com. You have started in the right place for sure.