After your comment on the longer wheelbase- I checked the "Z"-"F" and my Boreas in comparison. Of my road bikes- Boreas is my bike of choice for the faster rides. The shorter wheelbase does seem to suit me better although there is not much difference with the other two. Glad you managed to "Re-TEST" the bikes and found the differeence that suits you.

And those Ultegra wheels are my favourite. May not be the lightest around but they ride well and are dependable.