I know this info may have been posted before. Just thought I'd share the chart below. The data is straight from a Authorized Porsche Dealership/Service Department.

 

Unfortunately, the range stated for 996tt and GT2 models is NOT correct. [Should be Type 1= 6750 RPM and Type 2 = 6751 RPM and above.]
Seeing how incorect this is relative to the 996 turbos, I would advise verifying finding another resource before trusting it. I would love to know the actual source of this chart. I was told that UK dealers have what appears to be the same chart.

 

Gentlemen: CORRECTION. I'm horrified that what I posted conflicts with fairly new and 100% verified FACTORY data. I got into a discussion about this and in the process of communicating with the gent in the UK who supplied what appears to be the same chart. I was digging through a ton of factory tech info I have and had also reached out to a couple of well connected tech experts. One got back quickly with his data sheet, clearly direct from Porsche. At that point I stopped looking for my data as it's not significant anymore as it's just plain incorrect. OUCH. I HATE discovering that I'm putting out FAKE DATA. Please forgive me and feel free to throw rocks. I'm old, crusty, and should be able to hack it. [What I'm having trouble dealing with is finding myself putting out bad info.]

SO: It's veen verified and from here on I'm 100% with:
996tt/GT2 the Type 1 is 6750-7250 RPM
Type 2 is anything over 7250 RPM.
Period