Currently on page 214 of the first editing pass and not a page is free of red ink!
I found an easy way to invoke the banging noise. Put it in second gear and drive along at ~3000 rpm. Stepping on the gas causes it, as does suddenly lifting off the gas, so that’s good, sort of. Now just have to put the camera back there.
Found a small coolant leak but can’t get to where it’s coming from. Will likely require removing both seats and the firewall panels, or the fuel tank. Neither will be any fun.