Something to bare in mind.
The M-Sport suspension actually soaks up poor UK roads and speed bumps far better than the SE suspension.
The M-Sport uses a really nice Bilstein and Eibach strut and spring, where as the SE uses a really cheap Boge/Sachs set up.
Get an M-Sport on to 17" wheels and it feels much nicer driving round town or on poorer B roads than an SE on 17" wheels, get it off the run flats and it is sublime.
I have tested this along with a few techs at BMW who would not believe me.
So don't write off an m-sport, as you would always get someone with 17s to swap with the MV4s.
Plus you get the nice seats in a sport as standard, the SE seats are rubbish!
Also, I found the Lemon leather the easiest leather I have owned, I always went black, but got one with lemon in 2006 and was dreading it, but found it really easy, as soon as you saw anything you simply wiped it away, with black it just hides the dirt and then it goes shiny.
I have a dog and a 3 year old and would not consider anything but a light interior from now on, in fact when I bought my Merc I went with an Avantgarde over the Sport so I could get a light interior.