Nice To read, I have the sport seats and I came from a Volvo (where the seats are amazing) and the first weeks I had back problems, I really had to get use to the Seats of BMW, but now I am used to them, they are firm but give a good grip of the body especially when u inflate the side a bit
I liked the design of the X1 so much, I had to have one despite of the seats and now I even like them
they use this seats also in Mini Cooper and more models of BMW so after u get used to them they will be fine