USRT recommends close ratio gear boxes for any and all sport tuned vehicles with normally aspirated engines. (Those running forced induction, especially with big turbos, may do better with wider spread gears.) Tall ratios are available .71, .75, and .80. Unless the vehicle is a dedicated highway cruiser and only gears 1 - 4 are used when driving hard, the .71 is generally too tall for any enjoyment. The .75 is more reasonable but still presents a fairly large drop in engine speed in the final shift. Thus, the .80 (stock in Mk3 4-cylinder cars) tends to deliver best results. Our gears are pulled from working Mk3 transmissions, checked for condition, and then offered to the public.
The transmission does not have to be removed from the vehicle to access and replace the fifth gear. It may be done simply by removing the bolt holding the transmission-side mount and lowering the transmission a few degrees. Then, remove the wheel and the transmission's end cap becomes available to work on via the fenderwell. The whole operation can be performed by a first-timer within 3 to 4 hours.