I have to agree - the cost of the upgrade part by part will be more money than the value of the bike. Sell the bike (or keep it for a spare - a guest bike if you will), and buy the one you really want. I would suggest to anyone contemplating buying a new bike that they expect to ride more than a couple times a year to look for full 105 components at a minimum. Anything less and you'll be wanting to upgrade in a very short time.