Corrected entry: In the beginning of the film Donnie and Lefty are towing a Porsche behind Donnie's Cadillac. They seem to have the Porsche attached to the Caddy with some rope or maybe a leather belt (way too close together to be a proper A-frame tow bar). The problem with this type of towing is that any time the Caddy would slow down or accelerate hard the Porsche would slam into the back of the Caddy.
RJR99SS
4th Feb 2004
Correction: One can actually see an A-frame bar, with some rope tangled onto it. It is better spottable in slow motion, however can be seen if you look closely.