Stock lifters typically give you the best and quietest lifter for the money. I have heard that if you buy just the 12 lifters it's more expensive than buying the LS package of 16.

When you say redesigned, you mean with locating pins right? If the gaskets in your hand are black plastic frame, don't use them. Get the Fel Pro's with the T on the end of thepart number or the GM gaskets. They will have a metal frame and keep this issue from cropping up again.