You could get a 300 but as I said there's no difference in power I think only some had the tweaks from the factory. So you'll end up with effectively the same engine yet have more work to get it in for very little gain. I prefer the 200's the debate of 300 vs 200 is a debate that will never end until the supply of one dries up. The 200 personally is more robust.
Go for the auto box if that's what you want unless you can get a 300tdi with the factory horsepower of 120 odd then you'll end up doing a lot of work and not making much progress.
I'd definitely wait until you actually properly look over the vehicle with your own eyes instead of going by others opinions. The engine in it might be sweet as a nut and would be silly to swap it. Same with the chassis if it only needed a rear crossmember it's much cheaper to put a new one on and as strong as factory if your welds are good.
I wouldn't bin anything and scrap anything if it's perfectly usable.
Ok, well that's sort of made that decision then. One of the main criteria is that it will run on the waste oil just to keep the day to day driving costs down. I'm happy to put the money in at the beginning to get it 'right' as I only want to do it once. As mentioned previously, the auto box is for a nice lazy drive and so the wife can live with it.
I talked her into this instead of a Cayenne, I've got to get it right!!
I'm going to book it in for a MOT when I get home and take things from there but, as I'm going to need to source an auto gearbox and everything else that is needed, buying the discovery that's local to me does seem to make sense if she's good mechanically as I'll wind up with nearly everything I'll need in one go as opposed to buying things individually which always costs more and, I can use the discovery as a test bed to make sure it all works 100% before swapping it across.
One of the main criteria is that it will run on the waste oil
I talked her into this instead of a Cayenne, I've got to get it right!!