a bullet can wind up in the damndest places. I think the guy with the vette was shot, not shot himself. Friend of mine was at a resturant in vegas, there was a shooting and two bullets ricochet(sp) into his trunk. We figured they bounced off the ground and went in cause the holes were flat. A .22 is a small caliber, so thus needing 2 to the head, and even then, the highest grain .22 would have trouble breaking the skull. Even the old police issue 9mm hollow points are considered a small bullet. Which is why most departments in NJ are switching or have switched to a .40 (10mm) HP.
IMO, a 45acp, hollowpoint, 185gr will take care of any and all penetration issues.
Oh, and I wouldnt go near the Z. Bad kahrma with that. And since it was a suicide, you can figure why some foam is missing from the headrest.