The KBS shafts feel really, really nice.  When I was fitted for my AP2's and Vokey's back in July, my fitter and I spent a lot of time on deciding between the KBS and Dynamic Gold S400's.  Ultimately, we went with the S400's because they were giving me better numbers; I was launching the KBS's too high.  The KBS generally launches higher than a Dynamic Gold.  However, I really did like the KBS.  The up-charge for the KBS would have been $15.00 per club.  I do believe that you should get fitted, preferably by an Advanced Titleist Fitter.  I did, and the experience was fantastic.  I am going back to my fitter when the 910's are released.  Good luck!

In my opinion, the KBS shafts do seem to launch higher than my X-100's. However, with the new groove rules, who knows, that could be a good thing? As Johnny mentioned, you should definitely get fitted.

I got the KBS Tours in my AP2's this past spring.  I love the feel of them over Project X and DG.  I was fitted and do not feel that I hit the ball any higher than my previous clubs with DG shafts.. 

Make sure they check your swing weight on your curent set and match them up accordingly.