I have been out of car audio for many years but if I was building a system today I would probably use whatever head unit of decent make I had laying around or if I was getting new I would probably get a midrange alpine.

For front speakers I have always used mb quart components, rear speakers are not needed unless you got a suburban or some other huge suv. for subs I would probably get a single 12 inch image dynamics either idmax or id v.3 and for amps I would get something older off ebay from a good maker. I am still using a 10 year old phoenix gold m50, and they can be had on ebay for cheap when they are available.