Last year when I got the Box w/ 4yrs. ext. warranty, after driving it for almost 2 weeks, I took it to the Porsche dealer for Oil change and ask them to check if there's anything that need to be replace that is covered by warranty...and they found the ff:
Coolant reservoir bottle
Air bag computer thingy (don't excatly knows what it's called)
I forgot the other 3 items they found
my point is, it cost me to take it to the dealer (only one time for change oil) but the results are great. I use 1/2 of what I paid for my ext. warranty
and IMHO, you should do the same thing while you have a ext. warranty.
-Gerry