Originally Posted by jasonpero

I've heard them sound good and bad both ways. More often, they'll sound bad piggybacked off the rear speakers, but most people it sounds bad for can't configure their crossover properly (or don't have one) and leave their line level converter to the max setting. (well that's going to let the most bass through, right?? - yes - and the most distortion)
I just put in a rockford p3002 amp and a rockford p2 10". (Had 2 of them, but my factory highs couldn't compete) It's piggybacked off the rear speaker wires with a line level converter and sounds just fine after tweaking the built-in low-pass filter on my amp.
(Oh yeah, and it's not always about having to go through the pain of running some RCA's - Some people (like me) are still running the factory deck as well.

Either way - have to love that battery in the trunk.