FSA K-Wing Bar and OS-115 Stem Question

[Rockgrunt]

I rode a friends bike with a carbon handlebar (Easton EC-90) and noticed a huge difference in comfort (less road vibration) from my 3T Forgie Xl Bars and stem. So, I just purchased an FSA K-Wing handlebar, and am considering replacing my 3T Forgie Xl stem with a FSA OS-115 or the FSA carbon stem. Will changing out the stem make much of a difference in performance? Also, has anyone had problems with carbon stems from FSA?

Thanks!