GME AM/FM Car Stereo Radio

I haven't looked at one but it is a good idea to check the specs of any unit to see what sensitivity the receiver section actually has. The smaller microvolt reading is more sensitive as it is the actual electron flow created by the aerial to the receiver.
The GME unit may be quite sensitive, many popular radios/MP3 blootoothed, etc, are not very good despite the fancy multi coloured flashing led display on the front.

Built in mic for handsfree don't usually work as it tends to be to far away from the driver

While looking at radios I would thing about aerials, A better Aerial can also help in receiving a better signal.

Look at
http://www.mobileone.com.au/4b_amfm.html

https://www.gme.net.au/catalogue/antennas/amfm-and-mobile-phone.aspx
models aem2 and 3

https://zcg.com.au/mobilevehiclemount-amfmradio

It is important that when including an external antenna you use Low Capacitance coax such as RG62, Do NOT use CB coax RG58 as this will attenuate the AM signal, It will not however, attenuate your FM signal.
Peter S