Id say it all depends on the $$$. If u buy a low end jl vs a high end kicker...well kicker's gonna hit it harder. Do some homework and go to the stores and actually listen to the subs in the enclosure u want. Me personally, i'd get inifinity components (kappas) no matter what!! i've been in this game for a while and am sold over kenwood, alpine, clarion, cadence. kappas match boston but does it for half the price. GOod stuff.
amps....pg is arguiably the best...but it costs an arm and a leg. I'd go with alpine, audiobanh, or hifonics, lanzar, soundstream.
I'm running 6 kappas with a 800x4 and 2 1000 wat punch to pull my subs hx2. Thumps awsome but bass losess a lil after a coupla years
my next car im running kappas, with alpine amp and jl subs
or kappas and audiobahn amps and audiobahn sub