i like how everyone says sony is crap. in my girls civic we have sony xplode components, sony xplode head unit, and 2 12" pioneers in the trunk. sounds perfect. and everyone that hears it is shocked when i tell them its only sony and pioneer. in my 01 integra i just bought pioneer components for the front and rear last week. 6 speaker system only cost me $169 for the front 4 speakers and $69 for the 2 rear. im also planning on buying 1 15" solo baric for the trunk put in a custom box. which is going to come out to around $500 with the amp, custom box, and sub. like you im going with sound quality over how loud i sound from a block away. and the good thing about pioneer is that you can run it off of a good head unit like a Kenwood. and at a later date you could throw an amp on them and they will sound even better.
the main misconception people get is that they can run something like cerwin vegas, rockford, boston acoustic, or infinity, ir infinity kappa series component speakers off of the head unit. those speakers were more designed for amp usage and not running off of the head unit alone. best bet is to get something in the pioneer range that runs well off of a strong head unit that is still capable of running off of an amp if you so desire to at a later date. cost effective and sounds great either way