I've never heard of class G amps producing RF noise, and my Model 200's haven't given me any problems (even when I used them to drive my main speakers).

Never heard of class G myself, but class D is certainly prone to generating RF noise, because of the high amplitude spikes present in the circuitry, most of a few hundred kHz, and the harmonics of course.
So SOME care should be taken in designing class D amps, to avoid this.
Well screened cabinets and internal cabling, and compartimented units, should be sufficient to accomplish this.

Switching and tracking power supplies are sort of completely different things.

What happens to the S/N and THD in the M2200 when it delivers more than 80 watts?

Joel

You'd have to ask the Outlaws themselves for the details, but I wouldn't expect the signal to noise ratio and THD to exceed the rated values under either class AB or class G operation.

gonk & barend are correct. Class G is not technically switching, although it does "switch" power rails.
A true switching power supply actually breaks up the input power fromthe wall and switches it at a high frequency to adjust to the power demands at the output. This switching causes lots of noise, electrical, RF and in some cases mechanical. The filtering is critical to not having this noise get through to the actual audio signal.

Class D is a bit different in that it is switching the input audio signal, and adjusting the output based on the input demands. I have heard class D, but have not done any critical listening or measuring to see whether it has a significant noise contribution.
By far as others have said, with the exception of class D, a clean DC power is what all amplifiers need for the output circuits.