Thanks,
Well, the other ones are not textured so I guess they don't need to be, but maybe there is an issue with slipping that the texturing is meant to remedy. I really do not have much experience with threadless stems (coming from older quill stems) so I don't know what to expect. $50 seems like a lot. I just don't want to spend more money for something that will never be seen and won't improve performance or durability. OTOH, I don't want the bars slipping on me out on a ride. The nashbar adapter for example looks like polished chrome so maybe it might slip.

Here is the Nashbar adapter for comparison.