The US used 3 basic armored cars in WW2. The M3 White scout car looks like the front end of a US halftrack with a single set of wheels in the back. It had poor performance (although Gunnie R. Lee Ermey put one through its paces on "Mail Call") and was soon replaced.
The M8 was the same body as the M20 but it had a 37mm open topped turret. It was normally assigned to reconnaissance and military polcie units.
I've got the Italeri M20 and the Tamiya M8. Both compaines make both variants. Tamiya's is way superior to Italeri's, but there's nothing really wrong with the Italeri kit. The Tamiya kit is just nicer.