Porsche released a TSB on the 997 GT3 related to fix an issue with this stock weight pulley coming off when the lightweight flywheel is installed. So far I have not personally heard of this happening on the 996TT. I know their are alot of guys running this setup and I have not heard a peep from anyone other than the 997 GT3 guys. Here is a thread on it:
http://forums.rennlist.com/rennforum...track-diy.html

 

Interesting. From that article it seems to only be the 997 type?

I have a AASCO aluminum flywheel and have tracked it several times with no issue. Like you I haven't heard anything about our cars having issues.

 

Never seen that happen on a 996TT (done at least 10-12) and at least the same with the Aasco.

 

wow, first time i hear about this.

 

gt3 has less rotating internal mass then turbo motors so they will rev quicker up and down. like when you rev match the next gear. There was somethings about the lw pulleys coming off but they were remade to copy the new gt3 flange and shouldered area.

 

Much higher RPM has anything to do with that on 997 GT3 as well?