[danielspdx]

I used the NGK DCPR9E without issue in my '00 996 biposto. I had to switch to the R2525-10 for clearance issues, but the DCPR9E plugs will work with OEM pistons.

 

[danielspdx]

I'm running a modified bottom end with Pistal pistons, and the crowns contact the DCPR9E (and I have pictures to prove it), so I went with the R2525-10, which I had to order. They are about $25 each and available online or via special order from an NGK vendor or your local shop.