Well, If think the price differential of 100K is too much maybe you should see the specs on the truck. FYI, The reason the rear seats aren't installed is they have a rear dog (storage) platform installed. 
ER41 Supplemental Modifications
PowerTrain
  Stage III Bullet Proof Diesel Modification By BPD (Oct ’19)
  7.3 Cooling Fan modification
  All new Aluminum radiator by BPD
  Billet Water pump by BPD
  Coolant Shut-off valves installed
  Edge Insight CTS-2 Engine monitor with EGT
Suspension
  Hutchinson DOT approved Beadlock wheels
  Continental MPT-41 install
  King Heavy-duty remote reservoir shocks 
  Kilderman Airide suspension upgrade
  iLevel air suspension control
  Centramatic Dynamic balancers
Heating
 Replaced all heater coolant lines with NEW DUPONT Hi-Temp Silicon lines (Nov 19)
Electrical
  2 additional house batteries (upgraded) (1080 Amp-Hrs installed vice 540 per original)
  3000 watt pure sine wave inverter (upgraded)
  720 watts Solar Panels (upgraded) 720 watts
  New upgraded MPPT for solar panels(upgraded)
Communications
  YEASU FT-857D radio install with ATAS (MF/HF/UHF/VHF) 100W
   Remote satellite phone cradle install with exterior antenna (Irdium) and remote handset
   FLIR Camera 
Cab Amenities
  Full set of reflective aircraft quality insulated window shades
  Retractible windshield shade
  Rear Dog house install
  2- Rear Captain seats 
House Upgrades
  All Tinted windows
  Driver side storage compartment with cushions
  Gun Safe (driver side)
  Full length underbunk storage (approx 3” depth)
  Retractable bunk ladder
  32” LEDTV with 4-position mount
  Apple TV 
  Satellite KVH RV1 antenna install with DirecTV receiver 
  Sirius XM radio
  Thermal insulated plugs cab-house
  All granite top counter extension for galley
  Induction cooktop
  Upgraded 12vlt Compressor Refrigerator 
  Upgraded Leather cushions installed
  Hidden Biometric Safe
  LED lighting in kick panels and cabinets
  Exterior LED lighting 
It's a lot more than you think on the surface. One needs to dig deeper into the specs which no one did. You won't find a better more modified ER on the market for the same/comparable price. Just keep looking as this is a great deal with all the modifications and with ER quality added in.