I see you're getting some very specific answers to your question, but I'd like to offer some general thoughts: I think you ought to be able to get really good sound out of the factory head unit, if you replace the stuff *after* the head unit. Keep the factory head unit, but run it to an aftermarket amplifier and speakers, with an EQ in there if you need it. The JL digital processor is cool, but I suspect it is overkill and that you can get results just as good without it.
What I'd want to know is: Has anyone here done it? Kept the factory head unit but drive an aftermarket amplifier and speakers? -And how does it sound, and were there any problems in hooking it all up?
97 SE, teflon wiper blades, Dunlop Sport A-2 tires, Leather steering wheel cover, Pioneer DEH-P480MP mp3 CDRW head unit, Pioneer 12-disc changer, iPod hookup, Boston Acoustic 3 way 6x9'*, Boston acoustic separates in door pods, Alpine 4 channel amp in trunk. Magnaflow dual outlet muffler and Ractive stainless tips. Autozone rice pipe and K&N 4750 intake kit. Clear corner lights. Energy Suspension end links.