OK. I got a can of Turtle Wax Black Tire Coat a couple of weeks ago from my brother and finally had some time to try it out. Today had some sun so I tested it out on my winter tires. Here are the product pictures:
And here are a couple of tire pictures. I should have taken before and after pictures. They look like they are wet even though they are really dry to the touch. Takes at least an hour to dry.
If they hold out through the winter then I am going to do up the original 16" alloy tires the same. They claim up to four months; we will see. Thing is they won't be installed on the car for at least another month.