In just about any auto parts store I have been to in the US (Advance Auto, AutoZone, O'Reilly's, etc) both Pennzoil and Valvoline Synchromesh can be found on the shelves.
Any of the GM Synchromesh's can be found at any GM dealer.
Amsoil Sponsor Pablo can hook you up with the Amsoil MTL.
Not sure why you insist on ordering these items through the Internet when they can be found locally.