Stock exhaust nuts are copper and are made to withstand high heat and a lot of heat cycling. I'd stick with OEM if you can. If you have to use stainless for a short period of time, I'm sure they'll work. But for long term I'd recommend picking up some stock ones.

Audi and VW use the same style nuts (and they are way cheaper than Porsche) since they all use BW turbos. The local audi/vw dealers should stock them as well.

VW p/n: 11621711954
Audi p/n: 900 850 01

 

Stainless nuts are more then fine, they will not need to be replaced for any reason at any time.

Seriously just order up some Nord lock washers and you are good for a long long time.

 

Big thanks to Prestige Imports in Denver. One of their Porsche Techs hooked me up with a top end washer nut set up for free!!
Flew home a day early to finish up the install and it went fast and smooth. A few small hiccups but a quick call to Chad at Speedtech and a follow up call by John got me going again.
Fired it up and it's a beast!! This is the way a Pcar should sound YouTube doesn't do it justice. I have a little more fine tuning to do but check another project off the list!
If anyone is thinking of installing their own exhaust do it. Saves you $$, its relatively easy, and you get to learn about your car which gave me a greater sense of pride

 

These were my thoughts exactly! Congrats!