06 shaker 500 doesn't sound good, it can be "loud" but seems like equalizer is way off. Is there one main piece that's the crutch, I'm thinking it's the headunit and with an upgrade there the rest will be better? I am not going for full build, not too strict about quality and most time is windows down & listening to exhaust anyway but when I do turn on music I don't want to cringe

 

Do some research on Crutchfield, type in the make and model and they'll tell you what head units fit and what else is needed. But before you buy there check on Amazon, they usually have a better price.

 

That I understand, what I'm asking is our particular cars will replacing the headunit clean up the sound or is it vice versa the headunit "ok" but the speakers are the weak point. Not looking to go full replacement, adding amps, subs, etc

 

It's both. The head unit isn't very tunable. It's only got bass, treble, and front/back, right/left bias. And the mach speakers that are in there (from the older mach 3 system) are pretty good, but not very 'bright'.

I put in these, from of all places, Walmart. Cheap, but good:
http://www.walmart.com/ip/Pioneer-TS...eaker/46477424

They improved things quite a bit on my Shaker 500. Brighter highs, better mids and lows. Not perfect, I'd still love the ability to do a mid equalization, and seriously, the bass is a bit overpowering on talk radio.

Still, maybe worth it for the fronts. I did all four, because my rear window shattered for some **** reason, and the backs were full of glass, so rattles, and they were cheap enough to get all four, so I did. Easy peasy, slipped right in, and no regrets. Well, easy-ish, them back ones are a PITA to get swapped... not real sure who came up with that bright idea on those screws...

If that don't fit the bill, then you're into a full replacement to get your tunes the way you want.

Hope I helped in some way.