Weird 'chirping' sound, 2001 Boxster S

[FoFoJoe]

Interesting, I never would've guessed spark plugs. Wouldn't hurt to inspect or replace your spark plugs, spark plug tubes (or just the o-rings), and coil packs depending on mileage and service history. I'd be worried that taking a coil pack out could kill it if it's already about to die. Could crack the plastic or something like that.

ECS sells ignition kits.

Granted I would only worry about that if the car is 120k miles or more without any ignition servicing. And if you take the spark plugs out, replace those at minimum. No point in installing old plugs given how inexpensive but important they are.