I purchased a C&C 25 this year myself and the boat was outfitted with an old somewhat tired main from Newport Sails and a rather nice Dacron mainsail from Thurston sails in Bristol, RI. Since my boat was raced in Narraganset Bay for a number of years the sail inventory was pretty diverse. If I was going to get the maximum performance out of the boat, I would put up the newer main as well as the 150 Mylar genoa and then let ''er rip out in Buzzards Bay. For basic cruising and daysailing with family, I would just leave the old Newport main up and then let is stay on the boom under the sail cover overnight without giving a second thought about ruining it. You may want to give Bill Shore at Shore sails down in Newport RI a call as he is familiar with the C&C 25 and can make good recommendations based on the type of sailing or racing you are going to do in your area.