The Sonex firewall is stailess steel in a satin finish. It looks pretty good as-is, but machine turning the surface gives a nice touch. There are many ways to accomplish this, but I went low-tech. I used a 1" roto-lock scotchbrite pad chucked in a cordless drill. I laid out a grid on the firewall using a sharpie making 1" squares. From that pointm I turned the scotchbrite disc for about 10 seconds at each intersection. The pattern isn't exact, but it works well enough. It took an hour or two for both firewall pieces and the fuel tank filler box.
Additionally, I mounted the AeroConversions Smoke System to the firewall. I installed nutplates and doublers on the inside of the firewall to mount the smoke oil tank. The pump and solenoid are mounted to the engine mount tubes using cushion clamps.
NOTE: photos link to full size image