Bob Marley

Yes Guitar Rig 2 kinda gives noise especially on distorted channels and I have noticed that but when I applied WAVES X-Noise and Hum removing plugins in the subsequent slots of Nuendo's plugin slots practically almost all the unwanted noise seemed to disappear.

As far as WAVES GTR 3 is concerned it kinda crashes my Nuendo pretty bad every now and then and I have stopped using it. However other sound shaping plugings like hum and noise removal plugins from WAVES seem to do wonders and work perfectly as I have wanted it.

IK Multimedia's Amplitube 2 is a good amp modeling software especially on clean channels but Amplitube Metal seems to be little less than powerful (compared to distorted channels of Guitar Rig 2) to me though it is worth experimenting with.

I tried earlier versions of Rock Revalver as well, but just like WAVES GTR 3 it kinda freezes my Nuendo every now and then.