There are a number of sensors and actuators that connect to the wiring harness via these ubiquitous rubber-booted 2-pin connector Porsche uses. A time may come when you'll want to test the operating voltages at one of them, to see if they are getting a signal or to see if they are functioning. If so, get yourself one of these $13 connectors from NAPA, p/n CRB 2-18457.
It's a cheap alternative to the stock sealed connector, having a simple plastic shell and two pigtail leads. Soldering small duckbill clips (flat, not alligator, avail. at RadioShack) to these leads makes a serviceable breakout connector. Such will be useful in testing the signals to and action of the Vario-Cam actuator, the injectors, the Engine Coolant and Oil Temperature sensors, the Knock sensors, and the Tank Vent valve.
The duckbills fit perfectly into the stock harness connector (be sure to prevent the two clips from shorting, and to observe proper connector orientation) enabling active voltage measurement. Any voltage measurements should be done with a high impedance digital volt meter.
No peeling back the boot, no risk of pulling a wire loose. Back in the day, we would poke a sewing needle or pin through some wire's insulation to measure things (though there weren't really all that many things to measure). Today that would be a method of last resort, seeing as we don't want signal wires with compromised insulation, let alone to worry about finding the right wire when there are two or more inside the harness sleeve.
