Sensicore is just a "dampening" feature. If you get on True Temper's website (try the F.A.Q.'s), you'll find what you need to know there.

I play with the X-100 shafts. I personally don't like Sensicore because when I hit a bad shot, I want to know the feedback. I've hit clubs with Sensicore, and although they feel great, I didn't receive as much feedback as I get with my "plain `ol" X-100's.

Whatever you choose, just get what YOU want and what is best for YOU! Best Wishes!

Sensicore will add a few grams of weight when adding it to a shaft.  All other specs will remain the same.  I am a big fan of it and love the way it feels.  I can still tell when I hit a bad shot and the great ones feel awesome.  According to True Temper Sensicore absorbs more vibration than graphite.  Also several players on tour use it as well.

Here is what True Temper says about their SensiCore technology:

SensiCore is a vibration damping mechanism which reduces vibration/shock 70% better than other steel shafts and 25-30% better than graphite shafts. It is 14" long and is inserted 10" down from the butt end of the shaft. It does not effect the playability of the shaft. A club maker does not have to worry about cutting into it when tip or butt cutting. The only drawback is that you cannot swingweight the club using lead powder because you cannot cork it from the inside. 

Thanks,

Nick (1-888-Titleist)