Here's the deal. The TTRS pump does not work on all cars that it fits into.
The problem is the pump controller.
The TTRS pump can burn up the pump controller on most models. So far, only Golf R, some S3's and some SLCR's are verified to work with the standard pump controller.
However, you can buy this and know that it will work no matter what.
"Low Pressure Fuel Pump System
The APR Low Pressure Fuel Pump System is a complete, OEM style, PWM controlled drop in fuel pump and controller solution designed to fit cleanly in the OEM location. The upgraded pump provides adequate low-pressure fuel to the APR High Pressure Fuel Pump to support the power levels produced by the APR Stage III Turbocharger System."