Ah, 60k... lots of boxster owners start having problems with sensors at this mileage it seems.
If you replace the O2 sensors (all four), it might solve your CE problem. They may not need it yet, but will need it before the car hits 75k miles most probably. This will cost you about $450 and an hour of your time change them out yourself from under the car (I did it and if I can do this, ANYONE can).
When I did mine it was like I got an instant tune up. Purrs like a kitten at idle, gave me better acceleration and fuel economy, and my bald spot disappeared. OOOPS. Went just a little too far there... I'm still balding.
The MAF is located just after the air filter, which is located directly above the intake hole on the driver's side of the car in the engine compartment. So yes, the hard top will have to come off, the top raised to the service position, etc.
I would not try to clean the MAF though... some have found temporary success with this, but it is still a gremlin that comes back to haunt them.
www.oxygensensors.com has a good deal on Bosch O2 sensors with the correct square plugs on them, by the way.