Hoping for input re: Cervelo S3 v. (discounted) Oltre XR

[AMoon]

Hello all. Not surprisingly, given the subject, this is my first post. Please bear with me as I am only looking for the opinions of those with knowledge that is superior to my own. I currently ride a (M) Giant Defy Advanced SL 1. It is truly lovely, but I find myself a little too relaxed on it sometimes. Since I literally self-medicate by riding (20-30 miles a day), my wife has agreed to indulge me. And since my demons are very fast, I decided to get a more race oriented bike. More than anything else, I am looking for stable handling (i.e., not twitchy, "look Ma, no hands..." type handling). I have been looking at a 2014 Cervelo S3, which seemed extremely stable, but with taxes and just a wheel upgrade, it would cost me as much as a 2013 Oltre XR with Dura Ace Di2. Can anyone opine on the handling of the Oltre XR? I am also considering a Wilier Zero.9 (though I am very turned-off by the external cable routing), so I'd also appreciate any input on that bike.

The problem is that I've ridden the S3, but I have not ridden an Oltre XR or Zero.9. I know the advice is usually to just go with the bike that fits best, but I just believe that the Zero.9/Oltre XR would be a better bike if the fits are equal. I would appreciate anyone who'd go out on a limb to offer input.

TIA to any who respond.