Following this thread a little, Golden Eve. I'm pretty much just gonna reiterate what everyone else said here.

I think you are getting really great advice. It sounds like your ex is not emotionally capable of being mature, apologetic, or taking responsibility for his part. I really like what Prefab, Divine, and EskieLover said. Yes, I think that possibly, by going back and telling him what you really think of him, it *could* stroke his ego. He could be like, well well, she's not over me. Or he could just be happy in some twisted way, that he caused you pain. I don't know. Do you think he'd be that way?
What I do know is this: relationships and breakups can leave scars. Big ones. Gashes, even. I have some too. Anytime someone hurts us in a profound way, it really...makes a mark. I think thats what is supposed to happen. And you're not abnormal in...feeling that. You're also not abnormal in wanting it (the pain), to go away. It will go away. I just don't know if talking to him, yelling at him, or trying to hurt him back, is the way to go about it because 1.) he could end up hurting you all over again, and 2.) You may have mixed feelings about this because maybe there's be a certain way you'd say it, but do you really want to act the way he has acted towards you? I think you're better than that, and really, he doesn't deserve you or your words. I think your car being hit really may have triggered you to start thinking about this, and it makes sense. Someone hurt you (your car), didn't take responsibility for it, caused you grief. It is totally normal to be hurt and pissed after something like this (hurtful break up, being triggered, etc).
I think you should take care of yourself. First and foremost. Write it out. Write it here, journal it, when you're pissed. One thing I have done before, when obsessing about the deep pain someone caused me, is to give myself a set time everyday to focus on it. (I gave myself 30 minutes a day, and a specific a time, too). Its something I played around with. Just an idea.
I really think, living your best life, is what would be the best closure, too. It doesn't mean you're gonna feel sunshiney 100% of the time, all the time. But thats no one. That guy, your ex, sounds like a loser, and he doesn't deserve your time of day. Experiment with self care

This could be really good. It sounds like you're dating other people and having a fun time with that, too, and I think that's great.