Originally Posted by CACycling

Brifters, FD, RD, crankset, BB, cassette, chain. Before you start, determine if the frame fits you well and is worth the investment. Also, a Sora-level bike probably has a fairly low-level wheelset so you should probably consider adding that to your shopping list. Might find you are better off buying a new bike (unless you shop hard to get really smokin' deals on the components, you could spend as much on components as you would a new bike) and keeping your current bike as a backup/beater bike.