My Brother in-law used to apply this stuff all day long, it was called Diamond Brite, but the same kind of thing, preparation is EVERYTHING, and the end result is only as good as the prep work, the garage he used to work for charged around £350 to cover a Jag, and that was 8 years ago. He did my old Audi A3 and although it looked good when first done, I don't think it lasted more than about 3 month, so I went back to waxing.
Anyway he also gave me a trigger spray of the fabric treatment, which was really a Scothgaurd type protect ant. I felt this was a very good product, and used to spray my mats with it, which made cleaning them in the winter much easier.
Make sure the area you intend to treat is vacuumed and clean and dry, take the mats out and spray in a well vented area, leave to dry before refitting.