I just bought my wife a nice, one owner v6 cayenne and, before I give it to her, Im planning some upgrades. I've seen test pipes for the V6 in the past…but can't seem to locate any now. Anyone know??

I have the secondary car bypasses off my 958S…but I doubt they'd fit the V6.

 

Only thing i can add come's from Fabspeed's website:

http://www.fabspeed.com/958-v6-2011/

Fabspeed does not provide Cat Bypass pipe options for the V6 based on the above link.
So, adding a Cayenne S/GTS pipe likely increases the pipe size and thus likely changes pressure.

Then, the real question is what adverse impact would that piping size, pressure change bring... and would the benefits of bypass pipe still be worth the effort??

Regardless, good luck!