Models & features are constantly changing....Several years ago I acquired a full featured unit for my Challenger that today would be considered fairly basic.
About 4-years ago I found a Sony Digital Media Reliever(no CD) that was geared for iPod for my daily driver...lot's of features but the radio doesn't pick up all that well. Today I don't use the iPod (it died) but have a tiny thumb drive loaded with MP3s plugged into it's USB slot.
Put something similar from JVC in my Daughters car that had Bluetooth & she loved it.. Streamed Pandora through her iPhone..FM Radio tuner was good & sounded excellent with the stock speakers.
So it depends a lot on what media ya wanna play.. I jumped on Crutchfield to see what I might buy if in the market today & this one seems to have the most "Bang for the Buck" feature wise... This Kenwood stood out, I like the pre-amp outputs for one (for adding devices & amps) that many don't give you not to mention it has about every feature found on any Digital Media Receivers all for $99. Specs show it has a good tuner but of course I can't say having not owned one.. http://www.crutchfield.com/p_113KMBT315/Kenwood-KMM-BT315U.html?tp=5684
If all ya want is AM/FM/CD you probably can't beat this JVC, still it has most of the features of the Kenwood http://www.crutchfield.com/p_105KDR775S/JVC-Arsenal-KD-R775S.html?tp=5684
About any single DIN unit will install in an E-Body.. Most folks seem to cram it in through the front, I imagine they have to clearance the lower dash trim a bit as it would stick out some..
I went the other way & installed from the rear..you might have to make a custom trim for some of these to flush up like mine did, seems all have a curve in them now....
covered my install here http://www.cuda-challenger.com/cc/index.php?topic=21379.msg516377#msg516377
This trim looks like it might work ... http://www.crutchfield.com/p_120306229/Metra-30-6229-Dash-Kit.html?tp=3121
Rear speakers http://www.cuda-challenger.com/cc/index.php?topic=105098.msg1032746#msg1032746