Putting 2013 n51 in 2008 328i, would it be possible?

So, The N51 SULEV should be the same, but I would verify that with a salvage service who will ahve interchange information on hand. The N52 is visually the same, but different, and there are variations of the N52 that are part of a different line (not e90), so tread carefully on the N52. BMW electronic systems are not forgiving when you start mixing parts, though it can be done.