N55 exhaust on an N54 (E90)

I hadn't really looked at the N55 motor or exhaust until recently and Ive seen that the N55 exhaust seems to be much freer flowing than the N54. I did some searches but the only threads that came up were Bimmerpost and nothing was definitive.

I know Terry put an N55 mid section on one of his cars, but does the entire N55 cat back bolt up to an N54 chasis and DPs? Seems like it would be a nice upgrade with no secondaries and a built-in X-pipe instead of the resonator (E90 wise).