I would say it depends on what you are going to use the car for? If a track/auto-x car many folks remove the key start switch and install a kill switch and also a push button to crank the engine. If you want to keep the key then tap into one of the wires from the back of the key so that the pump gets power when key is on. Most auto parts stores sell wire, lugs, tee-wire connectors and it is easy to do. Here's a picture of what I did to my 914-6 and there is an additional starter in the engine bay so I can start the car from outside and look for leaks.
John Rogers the oldracer
