because the SNR and RS4 NMT are pretty similar I would suspect it to be possible. I have not had my hands on a SNT but I would think all it should require are some longer arms and NMT (off road) tires.
I'll see if I can find the link I once had for a similar project.
Ok here's the link
Looks like for off road he uses longer shocks in the upper holes of the shock tower. And dirt hog tires, the rest looks the same.