I would never recommend that you take a metal prop past its design rpm. My original posting was for those flying FP props, which can be designed for the higher rpm. My Lancair-owner buddy and great philosopher Oscar Grassle, when we were discussing this red-line stuff this morning over coffee, pointed out to me that in the 172 handbook, the operating power vs altitude is based on getting full rated, 75%, WOT, red-line rpm at 8000'. This means that at altitudes below this you must throttle back to stay at or below red-line. The TBO is based on this operation. The Lycoming is tested for certification to fly around at 100% power all day. So, why not on your plane, get a prop that will extend the red-line to the highest density altitude you normally fly at, and, like the 172, reduce power to red-line below that altitude, and benefit by the higher take-off and climb power. Besides, why do all your cross-country at the bumpier, more crowded air where the 172s fly!