I guess you could get a base car and add some options.
This is the reason I hate the term 'base car'. And why it's not used on the site pages.
If you're talking X-codes, that means a car without style trim. So a X66 L78 is a base car??
If you're talking engines, a car with power windows, dlx interior, gauges, AC, etc, but a 307 is a base car??
I'll say there is no such thing as a base car. A car with a base engine, yes. A sparsely optioned car, yes. A car without style trim, yes.