Any question answered...

I want to make my BMC lighter, how do I go about this? It currently has a Record/Chorus groupset, Easton ea70 wheels, ea90 stem, FSA Omega bars and a spec romin saddle. I know the wheels would be where I could save weight easily, but they're also really expensive. I cant' change the seatpost so I guess it's down to the groupset and stem/bars/skewers/saddle(not exactly heavy anyway).

Those components are'nt really heavy, and the the frame is heavy as it is designed mostly with stiffness in mind. So adding anything too WW and flexi, will be silly.

Obvious answer - lighter wheels, inners, and tyres.

Unless you have the same fork as me with the alu steerer. Thats a bit overweight in modern terms