I'm aiming for a 1.8 or 2.0 16V widebody with sportpack ...
.. but I'm happy to hear from the skinny 8V-ers too
Oh dear... this is all going to end in tears...!
Think "skinny" and "12 valves" dude.
Apart from the bits it shares with the widebody 4-pots (suspension wishbones) the skinny v6 is perfect and pretty much indestructible!
Bodywork - Look for a bit of rust around the rear near-side wheel arch. That's it.
The suspension wishbone arms are a bit feeble but the dampers (Boge) are very durable.
The radiator is likely to have been shot-blasted to buggery (peek through the bottom bumper slot and have a look).
Cam-belt etc. is okay. Just change it and the tensioner every 72,000 miles. Water pump shouldn't give any problems but if your old bus has tramped past 140k (and they do) and you're doing the belts, swap the pump too and then forget about them forever.
Brakes last well. Rear calipers can become lazy (check the rear discs are shiny).
Check for a lumpy idle.. some people slate the cheapo aftermarket MAF sensor they know they have fitted.. but the OE jobbie is pretty hard-core. Mind you, at that price you'd hope so.
Lambda however will die every 3 or 4 years. Use genuine, or you'll be doing it every 12 months.
Gearbox may start to think of retirement after 130,000 and the head gaskets don't make it past the same sort of mileage. Clutch is good for 70- 80,000 miles.. so with luck a clutch change/gearbox/gasket failure will all coincide at the same time.. take the entire engine/box out and fix it all at the same time.
The rest is just normal "car stuff". Rear wheel bearings may die, tie-rod ends will wear out (I had one or two of each) and you'll end up with play in the steering rack after 150k.
Exhaust lasts okay.
Electrics are not too bad. If the sunroof doesn't work it's the Webasto relay that's knacked, so don't waste time trying to fit different motors etc. Relay is about £30 though..
The leccy wndows can be lazy.. new window motors will fix it (so again, don't fanny about looking at relays etc).
Just check the oil levels and change the oil once a year (every 12,000 miles is fine) and the beast will last forever.