We all thought it was a bit strange during '650 initial training that the weight charts went up to 105,000lbs and the Fuel/CG charts went up to 48,000lbs. When we asked why, we were simply told that an "announcement would be forthcoming". Apparently there has always been room in the fuel tanks to hold plenty more fuel but perhaps to keep the aircraft within it's promised MTOW 6,000ft balanced field length this was withheld for later certification.
All existing G650's will be able to "Upgrade" to the ER specs for $2 million and a weeks downtime. All that is required is a software update for the plane view and FMS's (plus additional fuel sensors?), the required AFM, AOM, QRH and performance handbook updates plus "G650 ER branding" in the cabin (whatever that means) and a new data plate slapped on the tail.
I expect the ER versions will come with an ASC that allows operators to limit Max Ramp weight to 100,000lbs at their discretion to allow operations at TEB. The current 650 already comes with several such placards limiting max weights to 95,000lbs, 75,000lbs, etc, to allow operations at various weight/noise restricted airfields such as Sun Valley, etc.
The extra 4,000lb fuel capacity and MTOW increase really adds a lot of utility to the aircraft besides the added 500nm range, since we could now take a full payload on a 7,000nm trip vs being limited to 4 - 8 pax (depending on actual BOW) for this mission on the existing 650.
I'm already thoroughly enjoying the G650 as it is, I still haven't got tired of hearing other aircraft ask ATC,
"What type of aircraft was it that just passed over top of us?".
The ER improvement will make an already great aircraft even better.