Best Expansions for Car Wars Classic?

I'm venturing back in to Car Wars for the first time in two decades with the purchase of Car Wars Classic, and would like to purchase electronic versions of some of the supplements. I'm finding that it's a bit confusing to sort through the many supplements, some of which seem to contain overlapping contents, and it's not entirely clear which edition some are compatible with. Can anyone offer any advice, or maybe a "top 10" list of products that best complement CW Classic?

Best Expansions for Car Wars Classic?