Here's where I get mine.
Pap-Parts
There are also full tune-up kits available from them at
Pap-Parts Tune-Up Kit. Do not get the other tune-up kit they offer with the 4 electrode plugs. They do not meet the heat range specified by Porsche and can cause trouble in the long run.
If you use Bosch plugs they should be FR 7 LDC and nothing else.
You should at least do the
cabin filter and
air filter while you're at it.