I own a 1991 Supra turbo. While it's very fast (156 MPH stock, according to my Garmin GPS) you would have to change the gearing to get the Supra past about 165. The '91 turns 3000 rpms at 80 MPH and therefore 6000 rpms at 160 MPH. You can't go too far beyond this without really stressing the engine. I am really skeptical of claims of 170, 180... etc.