Bombur, I've had Ivory White Nappa in my 35iS for 8+ years & 110k miles and have learnt:
1 Gliptone's products work.
2 Be gentle. There's a temptation to 'Strip and re-finish'. Don't. Just don't.
3 Obviously, clean before you colour or condition. I use wet wipes.
4 Stay away from the Alcanatar as much as you can, then follow Gliptone's guidance.
5 Use sheepskin seatbelt covers.
6 When surfaces look a bit mucky, use conditioner on all the leather in the car at the same time (but not the Alcantara, of course). Then stick the wet sponges under the passenger seat.
BMW's Nappa is the best leather I've found in any car.
In absolute contrast, Alcantara in any car is a waste of time & money.