Have I missed the frame weight(s)? Can't just assume that Ti is "lighter".
Other than that, as everyone else - forks, tyres, saddle and cassette.
And....beware of diminishing returns. Even at my 9 st max, losing 1 lb off a 25 lb bike drops "our" combined moving weight by a less than massive 0.66%.
My bikes are always heavier than identically spec'd bikes and seem to gain weight between leaving the builder and reaching me. Now why is that....
Saddle weighs next to nothing, and the cassette it's a M950 pretty light Ti cassette, and these are two thing I wont ever change - as can't justify the outlay, and I'm happy with them.
If I can get a lighter wheelset at a good price, then I may well swap the wheels over (I like these as the hubs match the two mechs)
I don't know much about wheelset weights. I have always assumed M231's are pretty light weight, no idea about M900 hubs though. Any suggestions for something under £100?
I think forks for starters, Stem, followed by Tyres if needed and then we shall see.