I like the sound of w6v2s over w7. Sure w7 is louder and hits harder (bigger driver!), but w6v2s I think are more tuned to the sound. The bass drum pounds and other bass tracks rumble. w7 just sounds the same to me.
I'm getting 1 10w6v2 for my celica, with the custom box built up against the seat, so I can access the spare tire. Then, you mount the amps on both sides of the sub.
My advice, if you wanna hear it. Get your speakers and speaker amp at Best Buy. Get a cap, wiring, etc. For bass, get a w6v2 and a 500/1 monoblock amp at your JL dealer. The best subs i've heard, period.