I know I'm thinking way too much while watching Seinfeld, but when Kramer first saw Jerry's car on the highway, he didn't know yet that it had been stolen. What made him think that there were such good odd's that it was Jerry's car, when for all he knew Jerry still had his car? Also, if they didn't want to call the police because they didn't want a federal record, why didn't they call the police anonymously after the mechanic turned off of their route? What could they have possibly gained by following him all the way to wherever he may have been going? What would have happened when they got there if they had?
"Early to rise, early to bed makes a man healthy but socially dead." ---Yakko Warner