FYI,contrary to popular belief,the N54 is actually based on the M54.Thus the block is aluminium with cast steel cylinder sleeves,so as to be able to withstand the effects of forced induction.It has no relations to the N52 which was built on very different properties and requirements.
The N54 is known to take over 450rwhp on stock internals...as far as I know la.
Any idea how much boost the N52 supercharger kit is pushing? Wonder how long the engine would last