Base Radio Equipment
I still think we are lacking a little info on how your going to use your new rig.
I think if your primary operation is on AM a converted Amateur transceiver is not the way to go unless it was and older 70's tube type rig.
Today's Amateur gear are ALL VFO controlled, they are not channelized. You will have to tune every standard CB frequency with the VFO. You can waste memory slots programing them in, but again counter productive to the way the equipment is set-up.
Then you must be careful with the way you use them, a 100 watt transceiver running on AM must be turned back to operate at about 50% duty cycle.
Example would be 10-15 watts carrier and about 50 watts modulated output...anymore than that for long period of time and you will be paying for new finals!
I think you might be better served to look at the RCI/Galaxy/RF limited rigs if AM is your primary operation.
The ICOM rig you are asking about requires special microphones. Most aftermarket microphones require being rewired to use on ICOM equipment, they use a different setup with pin configuration and voltage on the connectors. This can be done of course, but shopping around you will see mics for sale stating wired for ICOM...once this is done you will only be able to use them on ICOM gear.
SSB operation is another story...if 99% of your operations are SSB...then you can make other choices...
I would stay away from using Amateur certified equipment for AM/ CB use if that will only be it's primary usage...
IMHO for the two cents it's worth...
All the Best
BJ