Prices I was quoted /actual were as follows:
Birds supply Quaife LSD £893.65 +vat
Birds fully fitted £1670 inc VAT ..as you say the 35i series has a welded crownwheel..
I was charged £165+VAT for a specialist to fit in Glasgow with 3 hours labour to remove and replace at B for BMW, labour rate as about £75 per hour.
So about £150 cheaper than Birds doing it..
From what I heard its a pretty specialised job as even the B for BMW guys contract it out.
Out of interest, had to take the car for its MOT and the roads were teh most treacherous I've seen yet here in the Scottish Borders.
A couple of hills, one with a very sharp, steep turn.
Both the zed scampered up on summer tyres with only a very little flash on the DSC on the first steep hill where quite often, non AWD cars just get stuck with one wheek spinning..I was taking it very very carefully but anyway..there you go!
2012 E89 20i MSport Auto Atacama Yellow, Fully loaded in its day.. changes /modifications (lots) full whippy here! 33 cars, 22 motorbikes,13 aircraft, 3 quad bikes and a tractor..the joys of the internal combustion engine..