well the NMS tuning guide says this Stage 4
This is the first point at which the engine must come apart. Assuming all the modifications at stage 3 have been carried out, the next step is the fitment of a ported big valve cylinder head. (Commonly termed a stage 3 head though lower spec heads can also be supplied) This will be coupled with ported and blue printed manifolds. At this stage it is essential to fit a hybrid turbocharger and depending on whether punch or top end power are your requirements either a stage 2 or 3 hybrid T3 will be fitted.. The engine will be fully setup and the fuelling adjusted accordingly. The boost however will remain at 18psi and the power will be in the region of 220bhp. At this level a suitable clutch will also be required and we offer two options at this power level.

Stage 5
The engine must now come apart completely, the bottom end being rebuilt to the highest level, featuring low compression forged pistons, and a fully lightened and balanced bottom end fitted with an uprated 4 paddle clutch. At this level I advise the fitment of our stronger steel H section con-rods as this is the absolute limit for std items. Coupled with a stage 3 cylinder head and camshaft setup and all the previously mentioned modifications, one of our double core Cosworth intercoolers is now fitted with reverse charge carrier. A 5th injector and MF2 fuel driver is now fitted, both the fuel and ignition ecus are fitted with new "chips" raising the rev limit to 7200rpm. The final piece of the jigsaw is a stage 3 hybrid 0.48 T3 and along with 23psi of boost generates around 260bhp and is what we consider the best all round drivable package. (Our Cosworth management conversion can be added to this setup instead of the 5th injector route for a more refined setup but power will remain the same)