I know this has been covered for the most part and after searching I havent really come up with a concrete answer.
I am going to buy a 3 channel amp to power my front components and 1 sub. I figure a line out converter is most likely needed but not completely sure on how many channels I need or which one to get.
Im really thinking about the arc audio XDi 803 WoofersEtc.com - XDi 803 - Arc Audio 3-Channel Car Amplifier
thanks for any help!
There are a couple things to think about. Your stock head unit has automatic eq settings so when you turn it up loud it boost highs and cut lows to keep you from blowing stick speakers. So you can leave it alone if your fine with that or get a new head unit or an active processor. I'm going to get the JBL MS-8 when I finish my audio upgrades. It will provide any outputs you may want (speakers and sub) so you don't have to use a converter all while actively flattening your eq so you don't get the crappy spikes and dips that your stock head unit gives you.
Second I would recommend getting 2 amps. One for your component speakers and a mono amp for your sub. Depending on how much you want to spend will determine your sound quality.