Will I improve the qualitry of sound?

I would say a lateral move at best...I would suggest going with an entirely different amp as opposed to staying in the Rotel camp...just my .02...

ALso..to increase your headroom my 3db one has to triple or quadruple your power...simply doubling it will not yield any significant results in this regard...

Spend some time on room acoustics. By far the best bang for buck when it comes to sound quality improvement.

I agree, this is a very lateral move. Same circuit, more power is really the difference if you move from one Rotel to the next. So ultimately all you stand to gain is better speaker driver control, with the same sonic signature as you have already.

Move to a different (hopefully better) circuit, and then you will hear the difference.

Good luck