We have the sock sails on our 44DS. Does someone have the “performance” version. Does the jib actually perform that well? Afraid the mast-furling main is a lost cause (Quantum Sails was honorable in saying a recut wouldn’t really improve things), but thinking a better jib might actually improve upwind performance.
ANYTIME you can get better sail cloth, it will improve the performance of the boat. Sails that are older and stretched out, as I am assuming the main probably is, will not perform as good as a new sail, even an older former top end cloth! With this said, usually the performance jib is a longer LP, typically a taller mast, so it has more sail area all together. Yes this larger jib will help performance. Some like myself have two weights of cloth for the largest jib, one where it works in 0-10 knots, another same size, but heavier for up to say 20 knots of wind. This does get expensive, unless you are racing, trying to get every 10th or hundreth of a knot, may not be worth it. Laminates do sail better overall than dacron, not that much more expensive, unless you go string style. Talk with a local sailmaker to get the best options for you and how you sail.
Depending how old and tired you current jib is, you could see a significant performance improvement, particularly upwind. A good laminate sail will out perform a dacron sail. Not only would a new headsail be flatter, the draft position would likely be better, since as dacron sails stretch the draft moves aft making them much harder to keep "in the groove". Another important improvement is likely to be the leech. Jibs that spend their lives on furlers, particularly if they have uv guards, tend to get stretched and floppy. My jib is suffering from that problem; it requires quite a bit of leech line tension to keep the leech from fluttering when eased out, and when close hauled it has a significant "hook" in the leech. Having a clean exit from the jib is really important to overall performance, because if there is a hook in the leech it creates turbulence along the leeward side of the main thus reducing the main's efficiency as well. It will also cause the main to backwind more, particularly if your main is already a bit too full.
Upwind performance is not so much about sail area as it is sail shape, and maintaining smooth, laminar flow over both sails. A bad jib can ruin even a good main in this respect.