I'd stay away from the 4JB1 as that's an 80's era diesel from the 1st-gen Trooper and even with the intercooled turbo it's not very well suited for the VX. The 4JG2 is what you want to look for, and you can find them typically complete with auto or manual trannys. I haven't yet seen one with TOD, but the unit from the 3.5DI Axioms and Rodeos should be up to task since they came with the beefier Aisin auto and 2WD selectable TOD unit. From what I've seen in the JDM service manuals it should mate right up, but you'll likely need to get a custom controller as the tranny's shift points are set up for gas. Personally I'd go manual to get the most performance, but you'd still likely need a custom adapter to retain TOD. At least the VX has a place to hang the clutch pedal! Advance Adapters may be a good place to query if you intend to keep TOD. Steer cleer of the 4JX1 as it's a common-rail mill and as such needs an ECU to run, whereas the 4JG2 doesn't care if you've got a battery anywhere near it once started.

Definitely stay away from any engine importer where they show photos of the engines sitting on concrete. If it's not on an engine carrier or pallet you could end up replacing not only the sump and pan but any number of ancillary components that were crushed or ripped off in shipping and handling.

The last time I went on a serious 4JG2 shopping expedition there was only one decent place in Japan and several breakers in the UK with fair pricing and good selection. That was two years ago but I ended up spending the funds putting our daughter into private school instead and now daily drive a Mk5 Jetta TDI while my wife uses the VX for her daily 20 mile work/school circuit. I still plan the convert as I believe a diesel VX would pretty much dominate ANY gasser VX. Not to mention I can't make gasoline but will soon be cranking out quite a bit of B100.

Good luck, keep us informed and be sure to do plenty of research before making the drivetrain purchase. There's absolutely no substitute for a well thought-out plan when it comes to vehicle builds as the details make all the difference when things start lining up, and that's definitely the better alternative to sitting in a garage full of worthless parts with an empty wallet and broken dreams.