I had oyster leather In my 335is and it wasn't too horrible. And the ENTIRE seat was white including the bolsters. One thing though, DO NOT wear blue jeans, especially new ones. They will absorb the blue. Definitely a deal breaker for me the next time around which is a bummer because I really like the ceramic white. Unless GM has done something to combat the blue jean bleed problem.
EDIT: apparently you can buy cleaners to combat this.
https://www.turtlewax.com/pro-tips/h...-leather-seats