[highteknology]

headunit, i would say Alpine, Pioneer, Eclipse (i personally have an alpine that i love)

spearkes, do you want component or coax? components have seperate tweeter and midbass where coax is all together. coaxes are cheaper, but you get better sound with components, for the most part. if you have around 200 for speakers i would say forget about coax and look at only components. Eclipse, maybe higher end Alpine, some people like JL Audio, CDT Audio, focal (maybe depending on prices)

as far as an amp. figure out what kind of speaker you want first, then look for an amp that will power the speakers nicely. i guess you could find your amp first then look for speakers, but that seems sort of weird (at least to me). as far as brands go, alpine, kenwood (maybe), JBL. you may be hard pressed to find some amps for your budget. it all depends on how much power and everything htough, so keep that in mind.