anything above a single D is too big. high B's and low C's are perfect in my book.
if the girl is insecure about them, and wants to have it done, then that's totally her decision. as long as she doesn't make them ghastily big (over a single D), then i wouldn't mind at all. although real does feel better.
for me, looks are like the bait. it's obviousley what initially catches your eye and what makes you move in, but once you get to know the girl, if you and her share alot in common or have similar personalities, you tend to forget all about the looks. (although they can be "appreciated" every once in a while
)