Yeah, these are definitely 2.5" vehicles that will not work with the 3 3/4" scale. I did take a picture of Hit & Run standing next to that 2.5" HISS Tank at the Con, but I can't find it for the life of me now. He basically towers over the HISS...the figure itself is almost as tall as the vehicle, there's no way he fits. I think the HISS will be around the same size as the 2.5" Night OPS VAMP, or maybe a bit bigger.
Justin