something must have not been hooked up right......I seen REF series subs with about 350 and they took it perfectly and got loud. The Kappa are supposed to be higher up too. Perhaps he had bad ones
They were used, and being run by a 350W RMS x 2 Kicker amp (old school Kicker amp lol), also used.
The install was done by a local shop the sells Kicker and Memphis. Although that hooked my subs up at 8 ohms to the amp...(Had to rewire to 2 ohms, since I had each sub running at 4 ohms). That was when I had my Volfenhags though.
i new a guy with 1200rms the big infintiy mono amp (well according to infinity) an he ran 2 kappa perfect 10's for a while it sounded great(except tweeter gave him double sub box and didnt make a wall...idiots it sound terrible turned up)anyway he messed on up when the tensile leads burned off...im am gonna buy both of them for 50$ 1 works fine the other...well can be fixed...cant wait till i get em