Just made this decision, C2! We sailed a Cap for a few years, loved it, put us in the fight for top NA spots (which we then gave back due to our own "grey matter"). The boat was great, had no issues, had a great opportunity to sell it and get a C2 (which looks to have improved on the only tough time to sail a Cap, downwind in big chop and breeze), so we did.

Fortunately new boats come with new sails! I generally believe that in what I have seen in NA to be fighting for the top 10% you need the newest kite you can afford, a jib that is new that season, and a main that looks like it is new, but is maybe two years old.

A good analogy I have comes from racing road bikes.... You can spend an extra $5k to shave 2 grams from the weight of your bike... or you can loos 5 pounds by eating 2 less grams of fat.... what would you rather focus on? Brand new sails are always faster, but until they are the reason you are not winning the race, focus on sailing better ;-) (and never rag yours sails, even to try your kite, bad bad bad)

(that said, if anyone wants a set of Cap main and jib used for only one week of sailling, message me)