John
We had a test drive in an Msport X1 (no xline available to test) and liked the sports seats (the test had the alcantara option) . My wife commented that they supported her back better. I found they held me in firmly as I threw the car around corners ;-)….all in the name of testing!
Both my wife and I are not that tall/big so the seats are a good fit. If they are anything like my dad’s 330e seats then we can’t wait for the car.