The next step beyond the Shift Improver Kit. The Transpak has all the features in the Shift Improver Kit. Most conventional automatic transmissions won't downshift into low gear above 15 mph, and automatically upshift at a predetermined speed no matter what gear you are in. With a Transpak you can downshift at any speed, you can also hold the transmission in first gear to any speed that you want. Stage 1. Heavy Duty For street rods, normal passenger vehicles or other heavy duty use. Firmer shift feel but not harsh. Improves transmission performance and life dramatically without loss of comfort. Normal automatic operation when in "Drive". Stage 2. Hi-Performance Street For full performance street use. Essentially the same as Heavy Duty mode except shift is much snappier. Retain full automatic features and standard shift points with selector in "Drive".