The pilot reported that in anticipation of a difficult approach and landing due to reported winds he configured the airplane early with the mixture-rich, propeller-high rpm, and the fuel selected to the fullest tank. He did not extend the landing gear due to the distance from the airport. The pilot entered the traffic pattern on a normal 45-degree entry for landing. On final approach he failed to perform the pre-landing checklist and confirm the landing gear was down. The airplane touched down on the runway surface with the landing gear retracted, which caused substantial damage to the fuselage structure. The pilot stated that during the annual inspection there had been an anomaly in the gear warning horn system and it was noted to be out of adjustment and had not been resolved. The pilot reported no other preimpact mechanical malfunctions or failures with the airplane that would have precluded normal operation.