1) ...some sort of driveline vibration at 45+mph speeds. A constant sort of rumble. .
2) How fussy is the independent suspension, alignment and longevity wise? .... Does the alignment get knocked out of wack from offroading?
3) How many of you have had the temp gauge or fuel gauge go wonky?
4)Are valve stem seal leaks a thing on the newer 3.8 trucks as they get up in miles?
This may not help a lot however here are answers with respect to our experience - 1st generation Pajero in Africa and our current 4th generation in Colombia. Note that neither was/is very high mileage:
1) driveline vibration - none in either vehicle.
2) alignment - perfect - the first was driven on very bad roads/tracks in Congo, the current one has covered lots of unsurfaced roads, rocky tracks, mud, river crossings, and dunes. No problems.
3) Gauges - no issues so far.
4) valve stem leaks - none so far.