Swiss are u a king about the standard pump that comes with the Stillen kit....if so here is the link to their pump as per Stillen.
ELECTRIC BOOSTER PUMP (EBP25) (12V) KIT - PART No: 9005 -
I've heard from others that they have stuck with the pump even after upgrading to the Frozenboost Heat exchanger, others have recommended going with a bigger pump but I could never get an exact part or brand for an upgraded pump.