Joe,
As stated the driven gear comes right out. But if your T5 is like mine. It has the red drive gear which is 6 teeth with the grey driven gear which is 22 teeth. That is the lowest ratio there is for that size speedometer set.
Please correct my math if I am wrong, but I believe the options are for 6, 7 or 8 tooth drive gears and 16, 17, 18, 19, 20, 21 and 22 tooth driven gears.
