i have the non turbo and dont know the differences but my thermo is right in the front of the engine. Follow the upper rad hose to it, above the power steering. But like I said, I dont know the difference between the models. But look in my signature and there is a link to the toyota service repair manual.
Edit: Try this.
http://www.cygnusx1.net/Supra/Librar...Section=CO&P=8