02-08-2014, 10:00 AM
Don't go back to them, they haven't aged well lol, and definitely take off those rose tinted glasses that you remember them with... 
But if you must, quick answer is stage 1 HDi is easy if you have a laptop and will do better mpg. Stage 1 XUD is easy if you can work out which screw does what on the pump and will be cheaper to run on veg despite doing less mpg.
As for reliability, I've heard a lot of bad reports of XUD reliability.
Both engines have their weak points, HDi's tend to be sensors, in tank lift pumps and crank pulleys. XUDs tend to be conrods and headgaskets....
Its down to personal preference, and I'd prefer the one that leaves the engine in one piece when it fails lol. But I also have diagnostic software which is useful for HDi fault finding, becomes more tricky without.
But if you must, quick answer is stage 1 HDi is easy if you have a laptop and will do better mpg. Stage 1 XUD is easy if you can work out which screw does what on the pump and will be cheaper to run on veg despite doing less mpg.
As for reliability, I've heard a lot of bad reports of XUD reliability.
Both engines have their weak points, HDi's tend to be sensors, in tank lift pumps and crank pulleys. XUDs tend to be conrods and headgaskets.... Its down to personal preference, and I'd prefer the one that leaves the engine in one piece when it fails lol. But I also have diagnostic software which is useful for HDi fault finding, becomes more tricky without.