One advantage to having a '98 GC is that you could use a Chrysler radio as far back as 1974 and the mountings should fit, and it will look correct (as possible).
Try this website:
http://www.elliottsradio.com/cubecart/index.php
I completely understand your logic, and buying a modern radio to receive AM is like buying a an LCD TV to watch B&W movies on... In other words, they suck.
Just about any old AM car radio will outperform any new radio on AM.