Don't "just live with it"! Don't do that! I won't respect you in the morning.

Seriously, if it drove straight after the tires and rims were put on and only started to pull, or drift, after it was lowered and aligned....

This eliminates tires and rims and a brake caliper possibly binding. So we're left with springs and an alignment. Personally, I don't ever remember a case where springs, themselves, causes a vehicle to drift left or right. And, I've done a few swapouts over the years.

Some history: I use a shop here in Houston to do all of my alignment work. The reasons are many, but as it relates to this case, I noticed that BMW has a tendency to only get the vehicle within spec rather than get it right.

What I mean by that is if the (as an example only) the camber calls for +1 to -1, my mechanic will get it to 0 where a BMW mechanic will see it sitting at -1 and go "it's within spec" and be done with it.

Find a copy of Roundel (BMWCCA magazine) or go online. They list BMW certified shops throughout the US. My shop is on that list. Find one in your area and take it to them. You may wind up paying ~$120 for another alignment, but it might be worth it to you if after it's done, the X tracks straight for you.

If you need help finding a good shop in your area, ask on this board or one of the others.... and then come back.
Good luck

If I was you,I would firstly eliminate the wheel/tyre problem by fitting your old wheels back on!If the car still pulls to the right ,you know its not the wheels.

Springs do not make your car pull to the right.

This leaves you with the aligment AND the lowering of rear suspension.
If you are left with these two,the dealer has to get it right or go somewhere else.