That does look good!
Interestingly, Graham Wood at Badcat on the Sussex/Kent borders also produces much modified versions of the 4.2 unit. He bases his conversions on the 4.4 Range Rover core blocks, crank and rods. He also makes his own special tubular "banana bunch" exhaust manifolds which greatly de-restrict a somewhat stifled area. I was tempted but I recall I was going to have to find a couple of thousand pounds to have them made for my X350R. Worth taking a comparison view by logging onto his site.
Don`t forget to add the ECU reflash, methanol injection kit, sports cats, high flow inter-cooler pump, three pass inter-cooler rad and ported out supercharger, elbow, inlet tract and small pulley. A standard 4.2 lump tweak easily and reliably to about 630hp. After that, they need a fair bit of strengthening carried out. A few ideas here in my thread about tuning the V8 motor in this link.
viewtopic.php?f=281&t=10761
It is worth noting that with that huge increase in grunt, torque increases massively. Gearbox and drive train components need to be up-rated to cope with the strain.
Mike K.