The stock clutch on my ix is not very compatible with boost pressures above 0.8bar, around 400Nm torque.

So I need a stronger clutch. Only problem is finding one that is reasonably priced and that will fit inside the bellhousing, and hopefully work with the throw-out bearing.

Stock m20 (ix) clutch:
228mm clutch disk
265mm mounting points for pressure plate
flat surface
'needs' sprung clutch disc
looks like a 240mm clutch disc + pressure plate could fit (if mounting points for 240mm pressure plate is same diameter as 228mm)
only good for ~400Nm, need 510Nm

The way I see it is that I have two options.

1) get a pressure plate + clutch disc for a s38 m5 engine
+ flat surface flywheel with sprung clutch disc, compatible with m20
- 240mm disc, so I don't know if it will fit onto a m20 flywheel
- expensive
??? diameter of mounting points for pressure plate, ie. will it fit onto a m20 flywheel?

2) get a pressure plate for a 330d (e46 2000-)
+ cheap
- unsprung clutch disc
- two-part flywheel, ie. not a direct bolton to a flat surface flywheel
- 240mm disc, however the 228mm disc two-part flywheel has pressure plate mounting points of 258mm (smaller than a 228mm disc m20) so the pressure plate for a 240mm disc might fit onto the m20 flywheel, with spacers to simulate the ridge on the two-part flywheel
??? diameter of mounting bolts for pressure plate

Any more ideas where I could get a reasonably priced clutch package that will hold for 510Nm torque?