from what i've heard they perform at about 250-300 rms very well, theres some kid around here with 2 of em banging around in his trunk, saw them at school last year, sounded pretty damn good for some budget subs
i believe 800watts is the MAX wattage (thermal)but only around 300 is needed to reach full excursion. i have 2 12s in my truck running off a JBL 600.1 and it sounds damn good. waiting to get a component system w/ a JBL 180.2 or something like that, then ill be good to go =) they preform really well in a 1.0cuft box (sealed) w/ about 1lb of polyfil per chamber. they awesome subs for the price. also take a look at the eD subs (elemental design) they look pretty good and arent too much more expensive than the VMAX. i beleive theres a post w/ the link going around on the board right now. dont ever lock yourself into one specific brand of sub. there are tons of them to choose from so dont feel enclined to buy on reflex. goodluck!