Mc, <br /> If the amp isn't stable @ 2ohms bridged you may be stuck with running it in stereo..If they were DVC then you would have something to work with. You best bet would probably be a small mono block probably 250 into 4ohms -500 into 2 ohms.(there are quite a few of these floating about). Just don't exceed 500 watts with 8 awg wire thats about the max for RMS current. Just a thought but a lot of Kenwood stuff as well as Sony, and Pioneer rate their stuff @ max input power on the box..So cut the power in half for a rough RMS power goal..If you do run them in stereo make sure you aren't going to clip the amp or you could cook the subs.
Your friendly neighborhood subaru freak!