If you're not too concerned with keeping the original(ish) look, I'd use a defender bonet and radiator support. Just means you don't have to move gearbox back, keeping original length driveshafts. The short rear shaft was an issue when i changed to ute cab. The weight coming off the back wheels made the shaft bind up making a horible/scary noise when i braked hard or hit the wrong bump. The defender setup means you can put a full length radiator like the original xf falcon (with auto cooling tubes internal) without the steering box fowling it and they're not too expensive.
The only other issue is frying tyres:twisted: and picking up the shattered pieces of discovery drivers when you leave them behind:D.
