In relative importance: source, preamp, amp. I personally would add speakers after amp on this list, though on this forum there are few that are like minded.
With regard to amps, please don't equate power to the ability to produce a quality of listening experience. If anything, as a rough rule of thumb, the opposite is true at a given price point. This is because it is much harder to make a good sounding 500 watt amp then it is a good sounding 100 watt amp. Your speakers at 4 ohm impedance and 86 db sensitivity do benefit from power, but a *good* 100 or so watt amp that is stable into low ohm loads is plenty for most applications in my opinion.
With regard to amps, please don't equate power to the ability to produce a quality of listening experience. If anything, as a rough rule of thumb, the opposite is true at a given price point. This is because it is much harder to make a good sounding 500 watt amp then it is a good sounding 100 watt amp. Your speakers at 4 ohm impedance and 86 db sensitivity do benefit from power, but a *good* 100 or so watt amp that is stable into low ohm loads is plenty for most applications in my opinion.