If you have Facebook, you should find the sales brochures from most years on the 'Mitsubishi Outlander PHEV UK' group.
Otherwise I'm sure when I was looking to see if a PHEV was right for me I managed to find the 2014/2015 brochure as a PDF with a few searches on Google.
In a nutshell though, on pre-facelift (ie up to late 2015):
GX3h - halogen headlights, basic stereo, parking sensors
GX4h - leather seats, HID headlights, satnav, DAB radio, touchscreen, sunroof, electric boot, electric heater, wifi connected app, reversing camera, heated seats
GX4hs - as GX4h, but with adaptive cruise control, FCM (auto braking before hitting something), lane departure warning.
2015 Mitsubishi Outlander PHEV GX4H (petrol/electric)
2008 Volkswagen Caravelle (diesel)
(recently departed - 2004 Subaru Outback 3.0Rn (LPG), 1991 Mitsubishi Pajero 2.5 LWB (WVO))