Twin piston doesn't work either as I discovered when I fitted the redundand one from my old RS Turbo for a laugh (it's designed for cars with a metering head). It just didn't work and would half dump before making a weird honking sound through the boost pipes. Relocating to the cold side is a good idea though as it will help prolong the life of the valve and move it closer to the throttle body. Audi, like many manufacturers, dropped a boob mounting it on the hot side of the intercooler so far from the throttle body. It has been common practice for years (on the occasions people run one at all) to resite to the cold side.