i don't do tri's but some of my good friends do. i would get a set of aerobars, a foward seatpost, and defidently some sort of tri suit. you could also get some tri specific shoes. they might be worth it. also, i would consider some smaller stuff like the holder for your food/water that goes between the handlebars, aerobar computer mount, etc... aero wheels would be great, but thats some serious cash....