Ok, short version.
1) He is 100 % at fault for this loss.
2) His insurance company, for NAPA and their driver will pay for the loss.
3) You were injured, and have what is called a BI claim. (Bodily Injury.)
4) Your car might be repairable if you press them the right way, or if not, you should be able to negotiate a very good settlement on the vehicle.
5) Do not sign any medical releases other than a medical bills and reccords release. Also you have lost wages since your missing work due to this.
6) They owe you a rental car for the time your out of your Supra. From the date of loss to the date they either make you an offer to total it, or repair it.
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I'm not a lawyer, so I can't give you advice, but here's what I'd do in your position.
1) I would not get a lawyer unless the other company pulls your chain.
2) I would make sure your fine. X-rays and other diagnostic tools are good to have. Your most likely going to be fine, but make sure your going to be fine. (It sounds like you have a soft tissue injury, or muscle strain and sprain. Lawyers like to call this "Whiplash".)
3) When your feeling better in a few weeks, it's time to resolve your BI.
Here is a good rule of thumb. If you have 2000.00 in meds, and 500.00 in lost wages, you should get 2500.00 cash, and the guy's insurance should pay the 2000.00 in med bills. (Or if you want to pay them, they give you 4500.00 cash... )
Everyone's slightly different, but matching meds/wages are "normal" in this business. Lawyers will tell you they get 5 to 7 times meds.. BULLSHIT! LOL Depends on the type of injury. IF your going to recover 100% then you get matching money at best. If you have lost an arm, or leg or eyesight or something like that, it's worth more, but again, ONLY if you have a permenent injury that will change your life.
My thought is the good news is the guy that hit you should have insurance since he's with NAPA. (Worst thing is when your hit by some asshole with no insurance, and no money to cover the loss out of pocket. Then you have to pay your deductable, and let your insurance company handle the loss, and try and recover the money owed. Generally they don't recover much, and it takes months and even years to recover if they do.
Good luck.