Upgraded my both my K2 and K8 with Keyboard Kustoms PE foam, poron kit, and POM plate, and the results were incredible. Beautiful, quiet marbled thock sound and terrific feel. It is now such a joy to type on these two boards! The KK upgrades are wonderful products and I highly recommend them.
Also, I messed up the case foam install (wasn't supposed to cut it) on my K8, and Rob sent me a free replacement! Wonderful, friendly service.
At this point, when I think about buying a new board, one of the first things I check is whether Keyboard Kustoms makes upgrades for it. Thanks KK for changing my typing life!