Fit a Davies-Craig electric coolant pump and controller. Either, remove the water pump and fit a blanking plate with water inlet and an electric fan or remove the impeller from the pump for a more stock look and retain the cooling fan. Either way, the thermostat gets removed. Fit an over-ride switch so that the pump and the fan can be run continuously. One minute or so of this after turning off the engine reduces the engine temperature greatly and might well prevent vapour lock etc in the fuel system.
Fit a modern light-weight geared starter. The much more rapid turnover speed made hot starting on my efi much, much easier.
Fit a Megajolt programmable ignition system with four coils. At the very least at 5500rpm there must be a lot more spark energy available than with one coil.. I have faith in iridium tipped plugs. The sharper the point the higher the electrical field strength and the more likely the plug is to fire in adverse conditions (hopefully).
More efficient exhaust
Fit tubular headers. Insulate the headers with exhaust wrap to prevent extra heat in the engine bay. (Also some say that preventing the exhaust losing heat promotes more rapid expulsion. Others say the headers may be damaged if they get too hot.) At the very least they look good! With the exhaust system, I understand the single pipe gives the best power but the twin pipes and balance tube the best sound. I've got one of each and I can't say I have noticed much difference one way or the other.