Because I can only recognize a few: the yellow car on the yellow one, which is the 2015 New Models version of D-Muscle (this one also appears on a gray sign), a white ‘original stunt brand’ sign with a Twinduction on it, along with another muscle car I can’t identify, but looks like a Mustang, and the blue one on the red billboard, which is the 2015 HW Race Team version of Rrroadster.
There’s also a red car and a green car on the same billboard as Rrroadster, and I can’t think of what they are. Any ideas?