I have switched back and forth between the wood Sensinich called for in the TC and an Aeromatic and I lost about 4 MPH at top end, but the climb and takeoff were so dramatically better that I figure that it was a great compromise. With the prop called for in the TC , I could barely make static on run-up. As far as the wing root fairings, unless you have the Houde STC or a 337 approving the Viking fairings, you are technically not legal. Houde made the wing root fairings and gear door fairings for the factory until the factory started making their own. My copies of the Houde STC and drawings were also lost in the fire. When Houde died, all of his approvals were sold to an outfit that only wanted his molds for Piper Apache gear doors, so the Bellanca stuff disappeared into the black hole of history. So many good, practical, safe STCs have been lost from the old timers dying , and no one able to renew the STCs. _____Grant.