I've been playing X-100's for many years' and decided to try the Project X 6.5 shafts on one of my previous Titleist Iron sets. I found that I actually hit the ball higher with them and did not like the feel of the Project X shafts.  If your looking for a lower ball flight, I don't believe you will find anything better than a Dynamic Gold X-100 to accomplish this.  Plus I wouldn't recommend changing to a different shaft if you have been playing Dynamic Gold for many years.  Just my 2 cents based on my experience.

Best of Luck!

I agree with Gator.  The Project X tends to launch higher with less spin for most people.  They tend to play more "harshly" too.  X100 with potentially stronger lofts can lower your ball flight significantly. 

what do you say . three strikes your out. im going to echo RC and the post above his sorry I didnt catch the name before typing.I'm a 10 year x100 guy. I've experimented withwith the project x line with no success. if u  were a S300  guy  I would tell u its a preference  thing but for the technical question your more concerned with I say stay x100. 

cheers greens and fairways