Well, I took a road trip this weekend and decided to do a temporary install. In all, it wasn't a bad set up. I mounted a VHF curly antenna to an NMO lip mount on the trunk of the G6 (No spoiler). I ran the RG-58 under the rocker trim and under the pass seat to the console. I slide the FT-2600M between the seat and the console. The radio looked OK there but from the driver's seat it wasn't very easy to view the display because of the angle. The mic went in a adhesive black plastic mic holder on the HVAC panal. It kept coming off. I finally restuck it and have left it alone with no mic in it hoping the adhesive will cure enough to cradle the mic. Not a quality piece.
The mic's DTMF panal is backlit in red, one of the reasons I wanted to put this radio in the G6. It is a nearly perfect color match, but just a tad too dim. If I dim the panal lights, it looks almost factory.
Anyway, we will keep working on a better mounting solution, in the meantime, this does work pretty well.