I have the 75, and I mounted the little antenna/power box in front of my stick shift, under the coin tray in my tj.
I use the 20ft stainless whip, works awesome. Tree-proof, and parkade proof!
I don't mind the speaker tho, the external is only really necessary at highway speeds with any situation other than the hard top.
I find I really need to turn the squelch up, but I'm pulling power from the internal fuse box, so a lot of internal noise translates into the radio, especially the wipers on mine.
But I like the 75, one connection, and the unit is out of the vehicle, quite the hidden install. Other than the obvious giant stainless whip on the arse end.
My antenna is an L-bracket, NMO style, using one of the bolts that holds the tire carrier to the tailgate, the bracket is notched in one corner where the tire carrier steel has a bend. Tough to explain, but you'll see when you look behind the tire at the carrier.
I also have the tailgate grounded to the frame with a riddly-piddly ground strap, so I highly doubt it works that well. The long antenna length helps, over 5/8's of a wavelength.