120k is a baby. The head gasket and gearbox will be the things to keep an eye on at that mileage.
Clutches tend to do 80k so if you can find when yours was last done, you'll know when the next one's due.
Have a look at the coolant and if it looks remotely not new, replace it with new 50% mix. While it's drained, take the opportunity to check that the low coolant warning light on the check-panel works. A new sender (top of the expansion tank) is about £40.
The radiator support bracket should be still available as it's an accident damage-able part.. about £20 from memory. Having said that, even a (front) head gasket is not available from AR, so if you find any genuine part, buy it.
While the rad is off, check out the bottom few rows.. chances are they've been shot blasted clean through. The v6 makes a good ICBM and while it's wafting along the motorway, the bottom bumper slots will channel grit/stones right onto the radiator.
The exhaust should have a lozenge shaped silencer in the big space you'll have under the n/s rear seat. It's not essential but it helps the back box keep the noise down, if yours is too noisy. Bosal etc. do replacements ~ £90.
The flexi-pipe is AR only unless someone can make one, which it seems they can..
Check the rear brakes for any discolouring. If they're remotely rusty put more bias onto the rear, using the brake compensator. If that doesn't sort it, new re-cond' calipers aren't tooooo frightening at £90 each.
Your dampers will make it to 180k if they're the original Boge. No worries there. I didn't have much trouble with my wishbones either, though 60-80k seems to be how long they actually last.
Cam-belt is good for the full monty 72k change interval recommended by AR so no sweat for yours. It'll still be immaculate at 144k but when you change it, change the tensioner too, as yours will be original. It's a blinding piece of kit.. but it won't do 216k.
Water pump is indestructible but at the next cam-belt change you may also want to change the pump (~ £90 for OEM part) as you have to dismantle the belts to remove the pump.
So don't worry about the mechanical pieces too much:- they're pretty bomb proof as long as you don't take the ****. Spend your money fixing the little electrical bits and pieces that fade away after that mileage.
Good luck with the beast...