Yes, I still have the silver one. I still wish I had the black one, but I don't care enough to try and sell it and buy a new one. My brother put the same valve (but in black) on his MS3, and I want to steal it but he says no, haha. I'd also like black couplers on the FMIC piping. Maybe some day I'll pony up the cash to do both (couplers and BPV). It's not going to change how the car runs, so I don't think it's really worth it right now.
The Forge BPV has a clear annodize on it, it's not just bare aluminum, so it shouldn't corrode. I am currently running with the yellow spring and no shims. With the TMIC I used a green spring I bought from Forge. It is even lighter than the yellow one. Springs/shims will have nothing to do with boost holding ability. They will simply control how quickly the valve vents off when you release the throttle. I used a light spring for quick response and reduced wear on the turbo. A stiffer spring will allow you to hold boost better during shifts, but could be harder on the turbo. Both the green and yellow seem to work OK for me. The blue tends to be a bit too stiff and I get some compressor surge.