yes I know they still explode, just not in the frequency as FO3
They don't. The vast majority of cars in New Vegas are the non exploding burnt-out-wreck variety. I've found a couple of trucks that exploded, and one bike, but that exploded like a grenade, not in a big fireball like in FO3. I don't think I've seen an exploding car yet....and I've been looking.
I really miss the moments in FO3 where you were fighting some raiders and then suddenly you'd hear the tell tale muffled bang, you'd turn round to see the car next to you burning and you'd have a few seconds to run to safety. Or the opposite, when you see some raiders take cover behind a car and you could fire a few rounds into it to take them out. It just doesn't happen in New Vegas
As for the destruction mod, it was a nice idea, I just don't think it was ever particularly well implemented. It was cool if you installed it and then went around shooting bookcases and chairs, but most of the time it was barely noticeable. It also added extremely annoying random deaths when you accidentally blew something up, and you couldn't use explosive weapons without destroying every ammo container in sight.