It was very hard for my dog to not be able to lay down on rides. This was in my husband's big rig, so captain's chairs...same sort of set up. He did not like being upright and wiggled around like that, but I know some dogs who are fine with it
I just think you're crazy for wanting to trash the inside of your nice car
And believe me... no matter how hard you try... it will get trashed. I have an Infiniti, and even putting cloths down/vacuuming constantly/detailing constantly, there was wear from him being in there. But that's beside the point
I'm not sure about the safety aspect of it, I always cringe when I see people with dogs in the front seat, but a good restraint harness would help a lot.