you wrote AVR, which means audio video receiver. you also mentioned it has enough power.
a quick look shows it is an am/fm receiver, not an avr, and has only 50 wpc into 8 ohm speakers. It is not rated to drive 4 ohm speakers, see the back plate: 8 to 16 ohm range is shown.
your speakers are high sensitivity, however they are 4 ohm speakers, not 8 ohm. thus you need to look at an amp's rating at 4 ohms, AND, it it has 4 ohm connections for 4 ohm speakers.
I agree, get more power, jason's recommendation is 300 wpc into 8 ohms
power needs double for each + 3db of sound level, so 50wpc, 100wpc, 200wpc, 400wpc. each increment only providing +3db increase.
IOW, don't think a 70 or 100 wpc is a LOT more power than 50 wpc. Thus, for those speakers, not necessarily to get louder, but to have the power/reserves to drive them, and handle instantaneous peaks, 300 wpc is not too much.
that parasound amp is expensive, perhaps the best choice if that price is in your budget.
to get into more affordable solutions, I would look for a less costly solution, perhaps 150 wpc into 8 ohm, with 4 ohm taps, particularly the type of amp that doubles it's power into 300 wpc at 4 ohms.