After Kerry asked about what fasteners were used on the firewall, it made me re-think (and re-do) some of them. For the most visible fasteners, I decided to use 10-24 stainless steel button head screws. I polished up the button heads on a buffer to make them shine before installing the screws.
This meant drilling out the stainless blind rivets and tapping in threads where screws attached directly to chassis. As a hint, use a drill made from cobalt when drilling out stainless rivets. Still a pain but works better than carbon steel or titanium coated drills. Using blind rivets is much faster but the button heads sure do dress things up better
I left the rivets in place across the top of these panels. The body has a lip around the engine compartment that covers those fasteners from view.