Even if you drive a car, good epoxy and factory style primer looking paint hold will up perfectly fine unless you think your driving the general lee and driving through gravel and off roading. New cars aren't even undercoated... my 230k mile 2001 truck still has primer on the underide and it's driven year round, mud/gravel, snow/salt etc.

There's no need for either other than the wheel wells and inner quarters unless you want to cover up flaws.

And I repeat, use bedliner on a car and see how people react when you go to sell it... if it's a valuable car, good luck! There's no need for it and no place for it on a muscle car.