Hi Chuck
Yes, it certainly drives better, but I have yet to confirm an improvement in fuel consumtion.
The WUR on my car it has a very thin metal diapragm under the plate with the four screws.
I didn't know there was more than one type.

__________________
Tony
76 W116 280SE
74 W107 450SLC
88 W124 300E
82 W123 280TE