You have two categories safety and entertainment. So would recommend safety over music choice
But as I like to ramble.......
I've heard a few things saying that LSD can be a bit of a handful in the R56, a "Both hands on the steering wheel" drive, not necessarily a bad thing, but it is something you'd want to test with and without to make a choice. It's one of those "Can I live with" items.
DSC I have. but sometimes turn it off to wheelspin, in normal conditions this is one that you should have
Heated Seats, my wife swears by them, if you have someone with a bad back go for it
now the stuff on the entertainment front:
Someone mentioned loosing the HIFI and going aftermarket:
HIFI versus aftermarket is a personal choice. I have the HIFI system, it's not bad, much better than the standard system, but won't be as good as a decent aftermarket system, but you get it in the car when you pick it up, so you don't have to take the car somewhere else (lose a days holiday)
You also then have grey areas if something goes wrong, was it part of the aftermarket install or mini fault? (As a Contractor I'd loose a day's pay going after market so it's doubling the cost of an aftermarket system before you start, so I chose the HIFI)
I'm not a HIFI guru though, so "you pays your money and takes your choices" (as they say)
I have DAB, if you normally listen to "BBC" stations and drive long distances, then it saves all the retuning every 10 minutes as you travel down the motorway. It does loose signal in some places, but then you have FM as backup, but it's a nice to have rather than essential and something you can drop off if strapped for cash.
I would agree with one of the earlier posts and loose the armrest
In Summary, in descending order:
DSC
LSD (Following Test Drive or with/without - preferably on same day / same route)
Heated Seats
Maybe loose the HIFI and go aftermarket (or not)
Loose the armrest
Forget about DAB
Erm and I just saw the post about getting them to chuck TLC in, good luck with that, but definately worth a try
Stu