Just finished a 3,500K in 3½ weeks, mostly bitumen road trip from home to Dubbo, Wilcannia, Broken Hill, Burra (SA), Lake Alexandra, Millicent, Mt Gambier, Hamilton (Vic), Maryborough, Great Alpine Road (Mt Hotham), Lakes Entrance, Dalgety (NSW) and back home.
All the modifications worked well, very pleased with the suspension (especially the Ultimate Aussie- Ryder shocks) when towing, set the airbags between 12psi and 15psi, think all air pressure the bags need is 12psi. The weight of the SmartBar on the front was not really noticeable, it seemed to have little effect on front end handling (Caroll's springs on front may have helped).
A couple of very hot days temp gauge was ok and found generally the best economy at 100km/hr was towing in S5 at about 21-22l / 100k. Tried S4 for a couple of fuel tanks, but economy was 23.5l+ / 100k. Everything seemed very nice at 100km with revs 1800 on flat ground and typically up to 2500 on steeper hills. The LC200 with the 2.5t single axel Kedron just cruised up the very twisty Bright to Mt Hotham road.
Overall very happy with the LC200 and Kedron combo and pleased with our modifications. The LC200 seems more stable towing (especially with the modified suspension) than the Pajero, though I thought the Pajero towed the Kedron OK.