After running my SSD's for awhile now, i sure can tell you theres gotta be something up with your setup. My 4 15's out performed by old btl 18s big time. Night and day difference. Great subs, and they can take the power if your smart with them.
Its not exactly about the equipment ran, its in the quality install. Hell theres a guy on here doing a 150 with 2 ssd tens.