Quick update: installed the Burger Tuning N26 stage 1 today (formal thread and writeup pending). Initial impressions, no change with the tip-in in D, but it is reduced by about 1/2 in DS. The car flies like a bat out of hell in DS, however. That's fun. Just a quick drive around the block and it feels like a whole new beast! A bit disappointed that the throttle hesitation issue wasn't fixed in D, however glad that now I have the option of mostly eliminating it in DS. I'm sure BMW will offer ECU upgrades for the tip-in like it sounds they are doing for the other N52/55 engines, but likely won't happen any time soon with the new model.
Insofar as the install went, it took me about 45 minutes, only because the instructions aren't specific to the X1, and there are some minor differences I had to figure out. If I had to uninstall it, or re-install it, it would literally take me less than 5 minutes.
SOLD Mineral Grey Metallic X1 s28i M-Sport
for sale: BurgerMotorSports Stage 1 tune