Price range 500 or so, maybe a bit more, any ideas? I want it to hit hard and sound strong

If you want some speakers that will hit hard and last longer than most speakers ive got some for ya. The new Sony XS-L121P5 12" subs are a great bargain and can handle up to 1200W max and are great sounding. Pick up an amp that will sufficiently power them at the correct ohms and you should be thumpin down the road well under your $500 limit.