I have an 02 and the premium sound sub sucked ***.... I think the newer cars have a better premium sound system.

I ended up just upgrading the sub amp, and now the system is on par with an average premium sound system. It is by no means great, but for sure acceptable compared to before.

what year is your car spartan? i forget.

For the 02s all 4 speaker channels are run to the little amp in the sub box. This is so that the amp can always produce base no matter where the fader/balance is.

then the amp has a cross over and a single output to the 6 inch woofer. I just cut the wires to the woofer and extended them out through a hole in the sub box. I screwed the amp into the bottom of the sub box, and hooked it up "booster style" For power and amp turn on, I used the auxillary power plug behind the trunk liner next to the left tail light. (need a relay up in the front fuse box)

it was a very simple installation. I had a small glitch in that the factory amp did not like being hooked up to the high level inputs of my amp, and everytime I switched the radio off and on, the factory amp would shut down. I had to reset the new sub amp to makeit work.

Eventually I figured out a way to keep the amp working, I added a resistor across the speaker wires and also a cap from one of the leads to ground. been workign fine for months now.