Nice one Jo.
My experience with the stock valve, the Forge DV006 and the Forge CL007P, has made me conclude that it all depends on the spring which is contained in the DV. The spring sits behind the piston.
Obviously the strength of the spring will determine how quickly the valve (i.e. piston) opens and closes.
I've found the Forge CL007P to work better than the DV006 on my unchipped S3. And is very close to the OEM valve in terms of responsiveness. Perhaps slightly more responsive, but I'd put them on a par.
However, I still get momentary hesitation sometimes, around 3500-4000rpm (3800 to be more specific). This was the original reason I changed DV's, but the aftermarket ones haven't cured the problem. And Forge have not replied to my last mail. /ubbthreads/images/graemlins/frown.gif
Anyway, I've digressed, good luck with the fitting.
AL