Try
Pelican Parts,
Auto Haus,
www.parts.com (which is Autonation, so OE parts) for items you need. Pelican has a console lid repair kit, I believe.
The Conti DWs are good tires. May also want to check the Hankook Ventus V12 Evo (I have them, very satisfied).
Recommend picking up the 101 Projects book from Pelican, very handy as is the Bentley service manual. I can't really comment on the spark plug tubes, but if it were me I'd only change them if they're leaking.
Box under the steering wheel, you mean? That's the shelf for the owner's manual.
Top treatment can be done with Raggtop, 303 Aerospace (which is available at West Marine, among other boat stores). Use a good convertible top cleaner and follow it up with a protectant to keep it looking nice (I need to do mine).
Boxster
)
Threaded Mode
