The most obvious place to start is sails. Sails have moved forward light years since 1980. You have likely seen old pictures of fleet racing, or promotional brochures, featuring boats with cross cut Dacron sails that are full in all the wrong places. Not only has Dacron come a long way, but today’s racer has multiple options in laminates. The greatest performance gains are as simple as upgrading Dacron sails for laminated sails, resulting in a faster sail in two ways.
First, a laminate sail has more stability because of the materials it is made from. It is simply less likely to stretch is ways that will slow the boat. Modern laminates incorporate carbon, Technora, Kevlar, Vectran, and Pentex, and have much lower modulus that Dacron and therefore better shape retention. That translates to more power, less heal, and keeping a sail up longer in a building breeze.
Second, a laminate sail is designed to have a more precise shape and maintain that shape. Whether a fiber path sail, with loading bearing fibers precisely aligned in high-load areas, or a radial cut with panels configured to accommodate sail loads, the result is the original design shape maintained in a broader range of conditions. That means the draft stays were it was intended to be, and minimal leach stretch.
I recently replaced a two year old Dacron blade with a radial cut Pentex blade on a J30. Not only was it an improvement in material, going from Dacron to Pentex, it was a design improvement as well. The new sail was radial instead of cross cut, and it incorporated a fuller leach and vertical battens. The results were astounding. No, unfortunately, I don’t have empirical data to support that claim, but the difference was obvious to everyone on board.
Invariably, the question of durability comes up, after all you are thinking, your sailing budget does not allow for replacing your sails every year.  That is definitely true of some laminates; they are designed and constructed to maintain a very precise shape for a very limited period of time, much like a drag racing engine is not intended to last 100,000 miles. If longevity is a consideration, most laminates are also available with taffeta, a light cloth, to improve strength and durability. While still performance oriented, they are also intended to last more than one season.
I doubt you can buy bias ply tires anymore, no matter how hot they were in their day. Modern design and materials produce a better performing tire, and one that lasts longer. The same is true with sails, and updating your great, older boat with new design and materials is a simple and very effective way of remaining competitive.
Now that you have decided to update your sails, the next part in this series will consider sail control. What modern innovations will allow you to maximize the potential of your new sails?