The SLS Power Package 1 is the perfect addition to your already potent SLS. ?With the gain of power and shifting speeds, just the simple software upgrades offered by Weistec Engineering let your SLS accelerate much harder and shift much faster than ever before. ?This happens because our calibration of your ECU unlocks your engines potential, and the calibration of the TCU shortens the time it takes to shift into the next gear dramatically reducing the time it takes to reach your desired speed.