Sorry to hear about your trans am, photo's made me sick to see but glad you are alright. You are well within your rights to refuse their initial offer. I had a similar situation with insurance company where they tried to low-ball me on a vehicle and I refused to accept their check. The other guys insurance was going to reimburse my insurance company in full for being his fault, So I fought it. No sooner than they gave me the check for what I felt it was worth, they dropped us from their company.
Hope all is well, let us know of any updates on trans am!