I have done many conversions on cars and motorcycles with factory parts from other models. My best recommendation is to first see which Kubota models use your same engine or look at as many different models that might have the manifold type you want and simply measure the studs on the head on your machine and see if they are the same on the manifold you want to use.
Just putting a turbocharger on your engine isn't going to work unless you can supply more fuel as the boost increases. Boost increase is dependent on more fuel. if you look at a diesel mercedes or 6bta Cummins in a dodge, there are fittings that go from the intake manifold to a diaphragm on the injection pump. As boost builds in the intake, the injection pump reads the boost and adds more fuel which helps to create more boost.
ONE Important thing also to realize is that the internals between a NA and turbo engine are different. Turbo engines have "heavier" design pistons and most have piston quenchers built into the crankcase that squirts oil up to the underside of the crown of the piston to keep it from melting. They usually have bigger oil pumps and connecting rods.
My 2007, 5.9 Cummins can generate 37 pounds of boost and not grenade because of the build of the internals. A Naturally Aspirated diesel, say an Old 7.3 Navistar in a Ford pickup, if you put a Banks system on it to add a turbo, they can only safely boost 5-7 psi or you risk engine melt down.
You will catch more FLYS with Honey than you will with Vinegar. don't take your marbles and go elsewhere as was said above. Just understand that the TRACTOR modifications are going to be a heck of a lot less than modifying cars or motorcycles.