I have a Look 595 Ultra (L - 56cm) and a Time VXRS Ulteam (M - 56cm) both with 110mm stems... I am also 6' with 32" pants inseam.

In my opinion I the 57.5cm Time is going to be too big for you. You can probably make it "work" with a shorter stem etc. but at the end of the day if a 56 fits you right a 57.5 is going to be the wrong size.

Unfortunately sometimes you just have to let a good deal slide...

JMR