With just 500 watta going to your sub....uh why do you need a cap?

And about your staging idea of giving the front driver and passenger their own set of left and right speakers is just :slap:

The drivers would be too close to each individual and trying to crossover that mess wouldnt be worth it...

take it from the masses and keep it simple... if you want to install a component set in the doors try out adire koda, rainbows, audio development..

if you want to try out kicks.. then by all means check them out..

Maybe you need to sit down and listen to some SQ cars that have both staged designs and compare the two..

Remember if you get a best set of speakers within your budget, a equally great amp (ditch rear fill) and a good install... you'll have a nice front sound stage.