I'm 45 and have had a pretty stressful career at times (20 years in the USMC as a helo pilot, airline captain now)
Here is my advice. Separate the event from your feelings about your car. Nothing is perfect. The best car made will have rattles and quirks and swirls and flaws and no amount of buffing, tuning or buying new will ever fix that fact.
I have at times transferred my desire for perfection onto things and it only brought anxiety. I would stress about car covers and fuel quality and rock chips etc etc etc etc.... It will make you nuts. maybe contribute to anxiety attack I dunno. It gave me marital stress. The point is, it is just a pile of parts all strapped together to perform a function. The Z is meant to shake rattle and roll a bit. It is a sports car. It is all about power, noise, passion, and fun.
My clutch rattles at stop lights (its supposed to) my exhaust Hisses (many do). my steering pulls in random directions at random stops (wide tires) the road noise on my (soon to be replaced) Hankooks forces my to wear earplugs on certain drives with "textured" roads. Steering lock fix, hatch rattle fix, hatch spring replacement, I could go on and on.
The point is, a Z is a quirky, "hairy chested" rumbling beast. That is part of its charm. You can tune and align and DynaMat the crap out of it and it will still at its core be a rumbling beast. Its not a sissy BMW M3 or 135 or a $80k Porsche to be driven by some turtleneck wearing yuppie stock trader. Its a car for people who drive with passion.
I say get her fixed! Love her (flaws and all) upgrade her so she is unique and special and all yours and remember that it is her dented skin and stiff frame that kept that SUV from crushing you like a bug.
A car is a pile of parts that can all be repaired and replaced, and none of which are ever "perfect" (though a bent frame is probably a death sentence to a Z)
Save your ideas of perfection for your love of people, your relationship with whatever creator you are into and for things with mathematical certainty. Everything else is flawed, and mortal, and temporary. Your car will *eventually* just be another pile of dust somewhere. Ashes to ashes and all that.
Perfection is unattainable.
Good luck my friend. I hope you feel better, and I hope the lawyers and insurance and rental car crap does not give fuel to your anger. Maybe the universe is speaking to you through this experience. It sounds like this is sort of a straw that broke the camels back type of thing.
Hang tough and I feel certain you will be laughing about all this in no time.