CL wouldn't have installed spyware unless you visited a url from CL that installed it, or you already had it. Anyway, spyware is probably not even involved. Retargeting is a common practice and why you see ads for a commercial site you visited on another site that's totally unrelated (including this one.) They just read the cookies on your machine.

If you visited that dealer's site, especially from a hyperlink on CL, that's all it takes.