Yeah. Like I said the price difference is marginal between this car's price and a US one. Though I found at least one that's cheaper and had DCT and Navi in the same color with similar miles. If you buy from a brand name dealer and not a used car lot, the chances you'll get a quality used car is much higher. Ultimately if you want to do the work you can find a better deal in the states. If you want to do the work that is.
As for the M button, it is just a preset for all the parameters that you mentioned. This is saved so that u can use them at a moments notice by hitting the M button. This is different and separate from the car's default start up state. Using iDrive I can easily set both but i believe u can set it via the control stalks also. Just more cumbersome to do so.