You'll be amazed at the difference this makes Sy. 
The check valve is the long black connector with two red ends at the bottom of that pic 
roger that. I wont be fitting it anyway

. Hopefully this combined with the APR coolers extra 29% volume will mean a substantial drop in temps from the 50-60 degrees it currently hits on the dyno.
A lot of the TT RS guys are beginning to use these kits now too.
A Porsche Turbo tuned for the kit will make around an extra 100bhp!!!! 
Were not tuning for it though, its only there for when were running on dynos, trackdays, 1/4 mile days and any other time it might be needed ie red hot summers days. Hence the toggle switch.
If i get 10Hp gain ill be happy