Hi Pacs. I've got a 98, 2.8GU. Been an alright vehicle once a couple of initial dramas were sorted after being bashed out of Mr Nissan. We've done about 176K, just done pump and injectors... which may or may not have needed doing as I think the MAF sensor was the main culprit. They are ok but remember it's a 2.8L - 6 cyl and not a 6L - V8, when the turbo runs out of puff it's about all over.
400K seems a lot of miles.. I reckon if you look you'd find one with a lot lower k's like around what mine's got, I think that would be around average of what I'd expect (the 180's).
Our agreed value for insurance was about $17k with our extras and that was about the max.
I've blocked the egr and added catch can, and the 3" inch exhaust has got it pulling just below 1500.
Check when the timing belt was done, and if the upgraded plate and gear has been fitted ( think it's dowled). They also have a problem with the harmonic balancer coming loose (or the bolt that holds it)...
If you want to do a lot of low speed lugging a 4.2 would be better..... and there are still some good GQ's out there or you could fluke an early GU DX model. DX doesn't have the back little seats, and is more vynal then plush carpet, and originally had the skinny wheels.
Maybe you could fluke one of those rwv conversions, where they chop the boot off and add a tray.
Can't remember exact price for egr block etc but prob around $400
injector tips - $700-$800 (fitted)
3" exhaust $800 - I fitted it
Timing belt etc $750 ( by Mechanic)
Paul