W3's r easier to wire up to ur amp for diff ohm loads w3's r available in dual 2, dual 4, and dual 6, so there a lot easier to find tha righ wiring for ur amp. w6's only in dual 6 ohm loads. and like wha every 1 else said, w6's r high power applications, w3's r more affordable, and dont need a lot of power ta make them sound good !!! In my old car i had 2 JL 12w3's dual 4's and a Rockford 250a2 and bridged mono ( 1 channel ) tha amp pushed about 350 watts , and those sub s made my ears hurt , gave me headaches all tha time. So u can have a good sound system wit 2 w3's and medium power amp !!