The Audi TT uses the same size rear control arm bushing as all TDIs (except the B5.5 Passat). However, these bushings are more solidly constructed and have no holes to increase their softness like th A4 bushings. Replacing stock and/or worn bushings with these are a popular way to firm up a TDIs handling and steering response. These are sold individually, order two to replace bushings on both sides of your car.