The sky is the limit, and as the old saying goes "How light do you want to go?? How much money do you have??". I would ride the **** out of it and spend some time adjusting the seat position and stem height to get every thing tuned to you. Saddles can be a place to spend a little money and save some weight but if it don't fit your backside it's wasted money. Decide before hand how far you want to go, 10speed or SRAM RED, maybe 8spd cassette and stick with DT shifters. When you have a written list of what and how much you want to spend you can start looking for parts or the next bike deal. Most of the time the next bike deal is the way to go and you finance it by selling the old bike or you become.....N+1