For the amount of effort invloved, you'd be MUCH better off fitting something good and desirable and mainstream.
If you're going to go off on a tangent from the norm, you'd be better off putting the effort into something extreme, like a VW Toureg V10 TDI or Audi 4.2 TDI etc. An early BMW M57 would be a nicer drive, more tuneable and far more reliable and cost effective. Probably cheaper too. There are parts availble for the conversion. Fitting an oddball means everything is custom and nobody wants it after. Those kia motors are pretty ordinary too. Especially once you have a cracked head, 4 poked injectors etc. Plus getting the ECU to run stand-alone is probably a drama.
While the perforamnce is much better than a 200tdi, they are a fairly horrible motor and expensive when things go wrong. And they do.
The problem with Disco 1's is that ANY conversion will cost more than the vehicle is worth.
I have a mate that will
give me his BMW 530d for free, but the conversion cost is far more than my disco will ever be worth, or how much I will ever save in fuel over the V8. I mean... that doesn't always stop me, though...
And I have done several engine conversions over the years. None of the them "made sense"... but they made a LOT more sense than a disco 1 conversion of any kind
And most cost more than the "recipient" cost to start with.