high preout or low preout doesn't judge how good sounding the HU will be....
it's the while HU by itself...the whole package....components used, circuit design, lens.....everything....
high pre-outs gives u advantage of having your gain in the amplifier to set lower... hence lower floor noise.....
and....higher pre-out tends to immune not to inteference than low pre-out
for me... a decent 4V preout is more than enough....... but the higher is better of coz...