I am looking at buying some Walthers Amfleets and am looking for some hands on differences between the new "Proto" series and the older ones that came in the tan/blue/red boxes with the window in the box (not the older ones where they are shrink wrapped in the box). I know the Proto cars have the "stainless" paint but I'm not sure if the details are a huge jump to justify the $60 per car, or the $25 I can get for the older cars.