I picked all these up at the supermarket here and there. Hotwheels scale OK with 15mm figures, but are a little on the large side if you stop to think about it. As I'm mainly intending these as city cover terrain it didn't bother me too much. I do intend to order some resin hover cars from Khurasan and 15mm.co.uk when I get back to England later in the year.
All I did with these was glue the axles then undercoat with a large brush and old Citadel Codex Grey. Then it was just painting and highlighting as normal, then using washes painted into the cracks (not over the whole model) to weather.