sorry i ended up workign it out for myself
N52 and N54 bellhousings are WAY different, starter motors are on opposite sides for one thing..
n52 starter is on the (facing the motor) right hand side
N54 is on the left hand side.
ED: all the ones i found were starter motor cutout being on the opp side.. guess they were all wrong
N54 trans pic:
these ics just show a single bolt hole different
probably important and either way, i have it now haha.. an te 53 is a bunch stronger :/
the prices on that site are INCREDIBLE too... 15000 SEK is like $2500 AUD
i got mine shipped to my door for $1200.
6000-7500 AUD for the N54 itself, also pretty high