Pretty sure the Sport variant of the e92 came out in 2007 ('57 reg), so they will all be N53's id imagine.
To be sure, you want an e90/91 on a '55 to '56 roughly. N52 has a grey silver engine cover, whereas N53 is usually black.
In addition, if you have a reg number, the BMW warranty checking tool will tell you whether its N52 or N53:
https://www.bmw-warranty.co.uk/Login/Index