Maybe look at these.
Street Duty SDC2.5-12-D4 Subwoofer
15" sub in tuned box
Hifonics XX-COLOSSUS amp
..i would not hesitate to buy either of these items, if they can be demo'ed before purchase....killer deals. Personally I like to use C/L, I do not like to tell ppl to use it, but u should know what resources are available to you....I NEVER use e-bay, just because the two amps i did buy on there did not work.....Check around and see what's available in your area. I have driven a couple hundred miles just to save a few hundred bucks.