My TR6 is equipped with Panasport 16X7 rims with General UHP 205-55 R16 tires mounted with 3 inch studs. The front suspension is stock and the rear suspension lowered using Goodparts competition springs.
The wheel / tire combination that I selected WILL lower the car. The tire radius is NOT stock. I selected my tire diameter based on the 3.45 differential that I have (stock is 3.71). As a result using this wheel time combination will result in speedo errors.
Please note that tire dimensions vary between manufacturers (and perhaps between different tires by the same manufacturer). As a result I could have stunning results with one tire size / brand and you could find only heartbreak.