Well, I got it in last night and somewhat working. But it sounds like total crap. I spliced into the rear speaker wires with the hi lo switch. Still haven't found a fuse that turns on in the ACC position, just one that turns on when the ign switch is in the ON position. The whole thing just sounds horrible. Something has to be wrong. The subs were fluttering and way too loud so I turned the pots on the hi lo switch down. But now they're just not hitting like they used to :(

I don't know how you can take a speaker level output with the 5% distortion of the factory radio, amplify it, and expect it to sound good.

Well the factory radio is only 5% distortion at max output. If you have a hi/lo convertor that takes the factory wires and converts it to low level, then hooks into the amp, it should sound fine. A buddy of mine just did this with his bose system so he could use his sub and amp with the factory bose speakers and it sounds great. You must have something hooked up wrong. For starters, check the polarity of your connections. Make sure you spliced and tapped the rear wires correctly into the convertor. Then look for a switch on you amp labeled "hi pass" "low pass" and "full" (or something along those lines). Make absolutely sure it'* in the LOW PASS setting. Then check youc gain and frequency setting to make sure they are in adjustment. Then on the other end make sure your sub is connected correctly to your amp. As far as the turn on lead, the car won't have switched power at the fuse box in ACC. Mine doesn't either, it will only be in ON position. That you might just have to live with.

Ok, I put it to low. Made a few more adjustments and it sounds better. Not sure on how to adjust the gain and frequency dial though.....

Use a very small flathead screwdriver inserted into the holes under/next to the corresponding label. Freq. would be: Clockwise for higher (bad) ounter for lower (better), gain would be clockwise for louder (tradeoff) and counter for softer. Mix these two with your headunit settings for bass, mid (if applicable) and treble where you normally have them and then adjust your amp settings.

my friend did this with his Bose maxima and it sounded like crap. aafter he put his aftermarket HU in the quality was 10x better

Yeah I might have to go with an aftermarket HU....we'll see how well I can dial it in.