In general, speakers with lower ohm impedance recieve more watts from amps but if it were to run at 4-8ohms and lower watts will this give it better sound quality? Going for a high quality system where money is no object would a high Ohm draw fed by enough amps (equal watt for watt of a 1/2ohm amp vs 4/8ohm amp) it needs be the best of the best. I've tried it and it almost sounds more responsive but my amp isn't capable of handling high ohm draw so it overheats and cuts off quite fast.
ex. 12" sub at 2ohm 2000w amp at 2ohm vs 12" sub at 8ohm 2000w amp at 8ohm
for a class AB cau amplifier, ideal load is usually 4 ohms for a class D amp, which I wouldn't use for a SQ system anyway, the ideal load can be 2 or 4 ohms depending on the amp design.
running at iseal load will give the best efficiency from the amplifier (most actual power converted to sound as opposed to heat) as well as the best THD, SNR, and damping scores. If you want a good SQ system, use class AB amplifiers fed with plenty of current and run them at 4 ohms.