There's a huge thread on the X1 forums of people complaining that their brakes wore really soon like yours under the 20K. I myself literally just did the brake job for my wife's X1 and we are at 45K. Some suspect the electronics are applying brakes to stabilize the car (can't remember if it was dsc or whatever nanny the car has). It does make some sense, and obviously a huge difference in everyone's driving habits. I have a tendency for most of my cars to just flip them for new brakes anywhere from 30-40K just out of habit. Sometimes the brakes get low, sometimes there's some brake deposit shake. Since I do the brakes myself and usually get them from aftermarket suppliers the cost is so negligible and I feel happy to have new brakes. I usually also opt for the drilled/slotted rotors mainly for looks since I absolutely love the look. There's many arguments both ways if you should or should not. I find that on big heavy cars like my minivan it does decrease the frequency of the brake deposits (wobble at brake). When I first got the van it was changed at least 4 times by the dealer since it would come back every 15K or so (once a year). After changing to the drilled/slotted style it never happens until I just decide to flip over the brakes (every 2-3 years just out of habit as I said). I'm not sure which rotors/pads/size the X2 m35i will cross match to since it is a unique car, but the regular style X2 matches the X1 size.
Edit.. out of curiosity I put it into realoem and it cross references to the same rotors as the X1 and X2! I could swear the rotors should be bigger.. so it's just the caliper itself that's larger?
https://www.realoem.com/bmw/enUS/par...&q=34106884002