I bought a 1981 Sundowner 18 a few years ago and love it! It's fast and very stable. I read that the 17' wasn't very stable, but info online suggests that the 18 was a totally different breed. Mine is toughweave and weighs in around 65 lbs, I think.
I had to patch a couple spots from the previous owner, but was pretty easy with a fiberglass kit. I took out the metal yoke and built my own wood one and built some removable yoke pads, also. After giving it a good cleaning, I bought some new decals from Wenonah, and voila, looks like new!