Here is my budget weenie.
As it sits, it is around 7.2kg (need to weigh still) without pedals, and has lost over 1600g
Total spent ~ $1100 (got a killer deal on the bike from a friend and ebay for all upgrades)
Started off life as a six carbon 6 with 105 and heavy everything including a carbon fork that weighed 728g!
Upgrades and weight savings -
Synapse full carbon fork- 434 g (294g lost) $40
Sram Red compact crank/bb- 746g (321g lost) $200
Vuelta corsa lite wheelset - 1575g (581g lost) $200
KCNC seatpost - 159g (115g lost) $40
Sram force derailleurs/rival brifters 627 g (283g lost) $300
Titanium Skewers 42g (89g lost) $25
total: 1636g lost
frame weight - 1419g (with hanger, seatpost clamp and cage bolts)
Obviously room for improvement. It would be nice to get to 6.8kg