They are looking better now... 
Thanks, actually quite fun assembling them.
I could have bought some with engines sticking out of the hoods, rather than adding engines,

... but went on the cheap with a box set of some futuristic looking vehicles and a Maitso box set of cheap basic vehicles, the better quality Hotwheel Matchbox I had laying around from gifts.
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Note for Modelers; the Hotwheels and Matchbox seem to all have an Interior, the less expensive Maitso, etc. seem to not. Only important if that matters.