I have not tried it on silver, but Lucas Slick Mist makes my red Focus shine like it is wet. I would suggest trying this product first before all the rest because it is the cheapest (around $7.00 bottle) and can be bought at most heavy truck dealerships.
It is very easy to apply and also makes your paint sssooo sssmmmootthh!!
The wet look you are talking about happens for certain reasons. First, minimal flaws in paint, the lighting affects wether this look reached. The other big factor is the paint itself........higher end vehicles like MB, BMW, Bently and the like have much better paint than Ford uses...so a factory paint job on your car is going to take a lot of care and work to keep looking that good.
I've seen only a handful of cars in my life that had the "wet look" at all times, night, bright direct sunshine, twilight, and cloudy days.