So I am planning to replace my audio system in my 2009 Elantra. I am going with HAT Imagine 6.5 components for front and back and a HAT 6.5 Subwoofer. So my question is, what type of amp should I get. I want a 5 channel for convenience. Is it really important to buy an $1800 amp. Lastly I have a Pioneer head unit that cost me about $300 when I bought it a few years ago. Is it that important to replace it if most of my music will we be played from my iPod as a very uncompressed audio file?