So here's the deal. I have this deck, http://www.futureshop.ca/en-CA/product/pioneer-pioneer-bluetooth-usb-mp3-wma-cd-car-deck-with-ipod-iphone-control-variable-colour-deh-6400bt-deh-6400bt/10190998.aspx?path=74b6400cb6cd970614ace4f923fdea16en02, and 4 of these speakers in my 2002 Suzuki aerio sw, http://www.futureshop.ca/en-CA/product/alpine-electronics-alpine-6-1-2-coaxial-car-speaker-sps-610-sps-610/10167593.aspx?path=a517282b99934641cc97b7de682878faen02. The stock tweeters are still in. I want an amp to power all the speakers, so any suggestion? I want to get a sub eventually too, so should I get a 4 channel for the speakers and a mono channel for the sub, or should I just get a 5 or 6 channel now? What other upgrades would I be able to do for the audio system in my car?