I just bought a set of stock AP2 714's with DG S300 shafts and I like the feel and performance.  I would like to go to a lighter shaft, having come from PXi shafts.  I have a set of Steelfiber i95 Stiff shafts that I could put into the AP2's for the benefits of weight and less fatigue on my aching joints.

Does anyone know if it would wreak havoc on the swing weight and overall feel or performance of the clubs?  Also, does Titleist use the stock head when using the Steelfibers or are there lighter heads for the clubs with graphite shafts?