I agree with Pandemon´s suggestion. Just put electric locks or numpads, it´ll most likely make everyone feel better and not to mention increase the car´s popularity since it will be safer.
Absolutely agreed.
Also, isn't a char with 10 CH, Outdoor 300%, 4 pathfinder perks , two Mentats and a brahmin in tow considered a 'car'? Or is it even better than one?
It doesn't cost gazillion caps, it can't be lost (think of your gazillion caps), it doesn't require fuel, it's not a trouble magnet if halted in open wasteland and it can't be stolen.
What have the cars or what should they have to offer to back up the extraordinary price and hard-to-get fuel MFCs?
I suggest them as a mobile tent location with limited stealth. They should be only visible to the owner and party members. (who knows the combination lock code) and become visible or vanish(like a tent after a week) after a day, if not retrieved by the owner.
That would suffice. Or should a outdoor bonus be added, so the driver can just drive past?
At least, that would back up the high price.