Both speakers advertise similar sensitivity, so if you're happy with the volume you get out of the amp now, should be fine. I'd expect some bass falloff at higher volumes with either of those speakers, though.
The largest difference will likely come from getting the drivers up off the ground and closer to ear height. High frequency sounds fall off off-axis, so unless you do your listening on the floor, you should expect increased clarity from either the taller Q4s or by putting your current speakers on stands.