Joined: Jul 2002
Posts: 40,863
Likes: 3,115
From: Sacramento, California, USA
Bikes: Specialized Tarmac, Canyon Exceed, Specialized Transition, Ellsworth Roots, Ridley Excalibur
FWIW, I had a CX bike that was cobbled together with a mishmash of Shimano groups: DA shifters, Ultegra BB and hubs, 105 RD, and a RSX (!) FD. Worked like a charm.
Save your money: you'll just be saving a few grams, mostly from your wallet.