The best thing you can do is save your money and go sailing!

Time on the water, getting the feel of response to changing conditions, practice tacking and mark-rounding, practice starts, etc... All those will have more dramatic effects on performance than a traveller or new sail.

Actually, "high tech" sails are legal under IWCA rules, but are not allowed in HCANA races; and travellers are not allowed in racing by either class association. So it depends on whom you plan to race against.