|The TTq, like the Volkswagen R32, uses an AWD system manufactured by a Swedish company called Haldex, rather than the traditional TorSen (torque-sensing) quattro system used in other Audi models. The Haldex is basically a control unit that uses a prop shaft off the rear of the transverse gearbox (02M, DSG) to control how much power the rear differential uses. Both cars are effectively FWD until sensors throughout determine that power needs to be sent to the rear, which, in stock form, happens with hard acceleration or loss of traction. The Haldex system on average distributes about 80% of the power to the front wheels and 20% to the rear wheels. In normal driving and highway cruising, the TT quattro is essentially a FWD car; when handling becomes an issue, the Haldex system wil send power to the rear wheels, but it will never go beyond a 50/50 split. TorSen, on the other hand, can send almost all its power to the rear wheels, depending on modifications.
If you want a more constant 50/50 power distribution, you can purchase a Haldex Performance controller... they sell for $900 new or around $600 used. This part will give you a more aggressive power distribution, and will allow more power to go to the rear wheels in any conditions, not just after front tire slippage. There are two replacement parts for the Haldex system, in the form of either a Blue or Orange controller; with the Blue controller, more power is sent to the rear wheels earlier, but the controller unlocks once the gas is released, or if the clutch or brake pedals are pressed. The more expensive ($1000+) Orange controller, however, stays locked.