I used the SubThump fark, their dual 12 inch enclosure, this Rockford Fosgate P1000X5 Amp
and 2, Rockford Fosgate P1S2-12's.
The amp provided an extremely nice improvement in the factory speakers. However the subs I can tell are underpowerd, I had a JVC mono amp in there and running subs only while I was waiting on the RF one to come in and it was hitting hard. That said it's probably exactly what 2ncd chance is looking for (with less bass). Just note that this amp will not fit in the factory location. I mounted mine on the back of the sub box after it was in the trunk making it accessible from the front of the car by putting down the back seat.
I will probably add a mono amp to my system just for the Subs eventually, for now the improvement in the factory speakers and having low end bass now makes me happy...