One of the biggest advantages of a remote mount pump in a mid engine vehicle like the GT40 or Pantera is that the mechanical water pump pulley usually protrudes into the cabin space (the hump between the seats), a remote mount electric pump allows for a flat firewall.
When I spoke with Meziere they recommended having the pump in the engine bay not up front in an electric only application. For connections to the block one can take and old mechanical pump and strip the guts out of it, weld over the shaft hole to create a cheap connection plenum. That is what I did for my prior KVA GT40.
As Howard states most systems overheat in traffic when there is minimal air flow assist over the radiator and the engine is idling i.e. pump at the slowest speed. In a mid engine vehicle there is a significant head loss with all the piping, bends etc. and pump efficiency can reduce significantly, be sure to account for this as pump manufacturers sometimes quote open flow rates. Although my earlier comment was dismissed, I do personally believe a dual 'booster' pump system is ideal in a GT40 or Pantera with long complex pipe runs, pumps operating in series have a cumulative impact, the increased inlet pressure of the second pump helps. The electric 'booster' pump only need supplement at idle in traffic etc. However, the Meziere is not a flow through design for a 'booster' pump application.