[Turd]

My 2001 Boxster (affectionately named Turd, recognizing its macadamia metallic colour and recent performance) has recently become an inconsistent starter. The engine turns over great and sometimes it will start just fine. Other times, hot or cold, it will take a number of engine revolutions before it starts to fire and then finally starts, then runs fine. No dura metric codes or engine light. It hasn't let me down yet but it's embarrassing and will wear out the starter and battery in time. Relevant work in last 6 months:
New fuel pump, new fuel relay, new spark plugs, new air filter, new fuel filter, new axles, new headlight switch, new transmission oil and engine oil.

Threads lead me to believe next step is the crank case sensor replacement. Any ideas?