I have just acquired a 2006 E90 318i 6speed petrol and I would like to put in a second hand diff but I am finding it hard to find one that is so called compatible, I see many for a diesel or 2.3 or 3 litres. I am not to worried about originality or performance would not one of these diffs do. I just want a quiet ride for not to much money. I live on the Isle of Wight and only do about 3k a year. Can any body help thanks DaveU.

Morning David

Two Diffs were used 3.23 = 1 in the manual and 3.91 = 1 in the Automatic 

The part number for the manual diff was 33107524318 it was used in the E87 E90 E90 LCI E91 E91 LCI E92 E92 LCI models 

The 2.0d has a final drive ratio of 2.35 =1 This would have an effect on acceleration and lower revs at cruising speeds which may drop the engine of its torque curve? How it would feel in practice ?

The 325 and 328i models I believe used the 3.23 Diff The 3.0d I believe used the 2.35 Diff

I believe they would all physically fit, it is purely the effect on performance to consider 

Good Luck I hope this helps 

Dave