The repair a squeaky floor is to fasten the underlaying floor more securely. While the treatment offered by the dealer will work, as you said it depends on repair of the carpet too. Suggestion: How about rolling the carpet up from the squeaky area, screwing the floor down, the re-stretching the carpet back down? Often tack strips along the edges allow this type of repair. The only issue would be if the carpet is glued down. Another treatment for squeaky floors in a home is to use special screws that go through the carpet to tighten floor, then the head snaps off, hiding the fastener under the carpet.
Bob & Donna
'98 Gulf Stream Sun Voyager DP being pushed by a '00 Beetle TDI