Due to the generosity of being given this mentioned speaker, I'll be dissecting the kes-5 to have a look inside and to compare to the truck stop available speakers. I haven't had much time to try it on the air but at first feel it's definitely a hefty one. The build alone is far superior to any bottom tier cb speaker of today.
Slow, as you mention with it being a 4 ohm impedance load it doesn't take much turning of the volume to produce sound. The clarity and frequency reproduction is much wider of any external cb speaker I've ever owned with plenty from the low to the high end. Hopefully I can do a report from a base perspective pretty soon.