Yes the outlets will make a difference on your guitar amps. Same as anything else. Only thing to keep in mind, since the guitar amp is essentially mono you obviously won't notice imaging or depth like you will with the stereo. But in terms of attack, harmonic development, decay, dynamics, sure. The only thing that would give me pause is the range of what sounds good with electric guitar is so all over the map you may actually prefer the grainier more distorted sound of a stock outlet. Oh well. When you're looking at building a whole room I doubt you will balk at swapping a few outlets.
As for which? Synergistic. Totally.
As for which? Synergistic. Totally.