I like the looks of shiny tires, but whatever I use doesn't seem to last.
Don't know what the dealerships use, but it sure looks sharp.

I heard a guy using black shoe polish once.

 

You might get more input on this over on the Automotive Care and Detailing forum. I'm sure some members over there could help you out, there is a lot of information on detailing over there.

 

GRPFAN, you can do a search in the Automotive Care & Detailing Forum like LexBob2 said. I haven't found a tire dressing that lasts though some are better than others. Stay with a water based product. They are typically a milky color. Silicone based gels are clear and give tires a better shine IMO but they can sling and dirt sticks to them more. Messy too. Make sure you clean the tires with a brush (use it only for the tires) before applying tire dressing. And ask your dealer what they use. They'll tell you.