Car Wars '65 Pontiac GTO and '63 Chevy II

A few weeks ago on Lead Adventure Forum the post on the 2017 Granite State Challenge (using Steve Jackson Games' Car Wars) was shared:
http://imgur.com/a/YwdUK

I've always wanted to convert Matchbox / Hot Wheels cars for something like this, but it's never been a front burner project for me. Well, that post above changed all that and I thought it'd be a nice little weekend project. I bought two Hot Wheels cars (at AU$2 each!) on Friday from the Reject Shop. The first was a '65 Pontiac GTO:

And the second was a '63 Chevy II:

After an hour or two the Pontiac turned into a mean looking interceptor:

While the Chevy was a nice little flamer:

The bits are mainly Games Workshop 40K weapons, along with plasticard (sheets and I beams). I think I might still add some mesh to the unarmoured windows once I find that in my modelmaking stash. I'll also need to use Greenstuff to fill in a few minor gaps.

Rules-wise I'm not sure yet, I've downloaded the free set of Axles & Alloys II here (off to the right hand side):
http://axlesalloys2.blogspot.com.au/

But Car Wars might be the other option. I'm probably going to buy another 2-3 cars to make a little squadron, most likely American muscle cars or pre-1985 cars. Haven't decided on a colour scheme yet, either blacks and reds for a speed demon crew or blacks and greys for a wolf pack.