Audi's first all wheel drive car was called the "Quattro", after that you could get different Audi cars with the quattro all wheel drive system. To distinguish between the two, the Quattro car is typically called UrQuattro among enthusiats, the all wheel drive system is generally referred to as quattro or the quattro system.

The pre-biturbo S4's are now being referred to as UrS4, and I am sure someone will start calling the old beetles the UrBug!