Those CC Product's guides are great IF they don't come brand new with a ID that is already half way to worn out. Overall fit wise, I think you might be better with BMW guides. Personally, I would install CC Product guides undersized and Sunnen hone them to fit. I would machine a sharper oil scraper on them too. I think it does make a difference.
I have seen those seats get hammered PLENTY of times. I would most likely change the exhaust guides too but I wouldn't change them at 60k miles just because.