I wonder if the non-disc frame is much lighter than the disc version
Non-disc is 2.7kg with fork, disc version 3kg (all according to Genesis).
Disc brakes must add 2-300gram including bigger hubs, rotors etc?
When I swapped disc for non-disc my build dropped by a kilo, although a lot of that was because I could afford lighter stuff elsewhere rather than spending money on the brakes.
Edit: frame + fork =2.7kg, Campag Zonda wheels 1.6kg, Campag Potenza Groupset 2.3kg, tyres + tubes 0.6kg, bars, stem, saddle and seatpost 0.8kg, so 8kg before bar tape, cables, pedals, QRs, realistically probably 9kg all in, before mudguards. That lot was about £1900 although I’m abandoning all my principles and shopping about on the Internet for those prices 😳