How many plugs for M235i xDrive is required? Please numbers for both Front and Rear seperately.

Your vehicle has 3 total. Two (2) in the front differential, and One (1) for the rear.

If I am changing the fluid in both the front and rear differentials of my 2004 BMW 330xi how many of these plugs do I need in total? Also does this plug fit both the front and rear differentials?

For total (two drain/two fill) for both differentials.

e90 2006 N52 330xi. Do two of these fit the front differential fill/drain and one for rear differential? Also, perhaps it would be better to update the item description to state that it fits fill/drain on the front diffs as well and that the rear diff can have one fill/drain hole.

The front differential uses two of these plugs, one fill and one drain. The rear differential only has one of these plugs as a fill plug.

How many fill plugs do I need for my 2013 328i xdrive sedan if I'm changing both the front and rear?

There are three (3) plugs in total.

does the fill plug come with the o ring

Yes, the o ring is affixed to the drain/fill plug.

Hello is this plug for the rear diff the same as the 2 plugs on the manual transmission? 2007 335i n54 manual transmission

No. The manual transmission uses p/n 23117531356 as the fill/drain plug. Currently listed on our site for your 2007 335i.

I have a 2007 BMW X3 E83. Will 4 be required for my vehicle? (2 front 2 rear). In the fitment list, it only specifies for rear.

2007 X3's only have a fill plug on the rear differential. You would need x1 plug for the rear differential and x2 plugs for the front differential.

Why don't you offer a magnetic drain plug?

Doesn't serve much of a function in the applications in question. A magnetic plug will capture some wear material but a majority remains suspended in the fluid which will be removed when performing a drain and fill. In addition, on later model vehicles where there is no drain plug for the differential it serves even less of a purpose.

I have a e46, 2002 325xi. Does this plug fit both front and back? I ordered this part earlier for the rear, but did the front first. While the dimensions look the same, the new plug has an o-ring and no washer, while old front has a washer & no o-ring.

Yes, the same plug is used for the drain and fill for the front and rear differential.

Does this fit a 2013 335xi transfer case ?

Yes.