Ok guys... it's been a while since I shopped for any audio stuff.

Help me replace the Sony stuff that came with my 03' FW's H220. The head unit is starting to wig out so it's time...
I don't need the latest and greatest... We don't play our stereo a ton but it's nice to flip it on now and then. I'm seeing units for around $150-$200ish? I see several are happy with the 6.5 Ininity 612's for my front 6.5's? I need to peak at the back speakers... I don't even know what's back there... but they don't sound the best either.
Would the current Sony head units just plug into the current wiring? Or do I need a kit... OR should I avoid Sony all together?
A few years back... ok, it's been 20 years since high school... I was the guys that tinkered on this stuff for buddies... now I don't have a clue as I'm content with the factory stuff in my cars/boats.... so I'm at your mercy for suggestions.

Thanks guys!
btw... Amazon.com.. Crutchfield... or ??