The body kit isnt the same between an M5 and M-sport. As well as the other bits you mentioned it also has different front wings. I agree though its a bit pointless, plus you will look stupid sitting at the lights with the deisel clatter coming from what looks like an M5.
My neighbour has an e60 M5, a ridiculously impressive car. Looks quite different to an e60 520d M sport which another guy in the same street has.
Thinking of doing something like changing a standard e60 to look like an M5, just because it will look more individual than a standard car. And i can confirm that genuine M5 front bumpers are wider than M sport, thus requiring wider wing panels thereby achieving the more agressive look
Probably start with a 525d or 530d manual and go from there, ecu remap, sprint booster (if they actually work, opinions needed), lowered 20 -30mm, the correct staggered 19x8.5 and 19x9.5 front to rear M5 alloy wheels, get rid of the run flats and uprate a few engine parts. All in all i reckon you could get a 530d to do a 0-60 run in about 6.0 secs (standard 235bhp is officially 6.8s). A good driver could keep up with an M5... until the M5 driver hit the 'M' button, he'd smoke the 530d after that.
Plus 44mpg (officially) versus what my neighbour reports to be 13mpg for his M5 is a big bonus.
Saying that, i would just get the bodykit and front wing vents because i like the look. No M5 badge on the back or anywhere else, thats a bit daft.
Here's an example of what I don't want to do, a bit OTT with M badges dripping of every lever, facet and panel.
http://www.pistonheads.com/sales/527560.htm
Not to my tastes but each to their own i guess.