Originally Posted by djtodd

The CSC failure is most likely due to heat. Hard driving, regardless if you are shifting, is generating significant heat.

To answer your earlier question though... Hard/high rpm shifting will certainly be harder on the clutch, fluids, and csc, than staying in third, but not eliminate wear, or the need to change fluids appropriately.
Once you do it once, you'll see bleeding the clutch is a REALLY simple job that goes a long way.