OK Vegas 1, four Captain Obvious questions:
1) You mentioned Meg's D110, which number corresponds to their HyperWash soap. Did you mistype/transpose the numbers and mean D101, which is their All-Purpose Cleaner (the light green stuff)?
2) Was the salt-and-grime in the pics from a full winter's worth of getting in-and-out of the vehicle's use-and-abuse?
3a) What make and model of vehicle were these mats from? (not that it matters, but I do NOT think you run the beautiful blue Mustang in your avatar pic in the salty New England winter, do you?)
3b) I also assume these mats replace carpeted floor mats for winter's use in the fore-mentioned vehicle in question. OR, do you leave them in year-round?
4a) You mention ed getting Koch-Chemie locally. Who are you buying that from Over-The-Counter?Just curious....
4b) Are you using Gummifix GUF protectant on other interior plastics-and vinyl trim as well??
4c) Any comparisons to other vinyl protectants you have used in the past?
(OK, it's seven different questions, kinda. You are NOT very good at counting, Captain Obvious, are you!)
Mats look very nice and like-new shiny. If this K-C GUF protectant is not that greasy or slippery as you say, you may have found a product alternative to vinyl- mat-specific-cleaners like WeatherTech's or McKee's 37