R.T. Quaife Engineering Ltd. Since 1986, Autotech has been importing and distributing Quaife differentials, first for Volkswagen and Porsche then gradually expanding the range to cover more than 120 applications. Our longstanding, working relationships with several car manufacturers at the race track have evolved into new relationships with them at the original equipment level for performance road vehicles. We have supplied Quaife ATB Differentials as original equipment to DaimlerChrysler and General Motors.