Question About Density: Lower Mass, Same Volume?

[Sundown444]

So if a car were to somehow have its density lowered by lowering the mass, but keeping the volume the same, would the car be more damageable and breakable than it was before, or would that depend on something else other than density?

 

[phinds]

So if a car were to somehow have its density lowered by lowering the mass, but keeping the volume the same, would the car be more damageable and breakable than it was before, or would that depend on something else other than density?

I would depend on lots of factors. Surely you can image material such as composites that are MUCH stronger than existing car material but also lighter? Such are not used because they are prohibitively expensive, but ...