rbuike wrote:

More than likely an "off road" version. Cervelo does this with the R3 as well. There is a slightly different build for P-R and other "rough" races. Little more ground clearence, wider fork and stays for 27mm tires and a slightly longer wheelbase.

possibly, but there's a few thing that puts it into question:

#1: Strade Bianche isn't a super rough race...it's rough unpaved roads but nothing like PR. If you look at other teams they use standard S-Works SL4 and even Gilbert uses a standard SLR01 (not the modified version)
#2: The changes on this bikes don't seem "small" such as more tire clearance modifications. Compared to current Madone 6, The whole fork is different, the seat stays have a split at the top instead one-piece wishbone, and top tube seems slightly curvier.