UPDATE--An email reply from VisionTech:
"Integrated bars are mainly sold to athletes that already know their ideal fit position. Since integrated bars are connected by welds, thus eliminating heavy hardware such as bolts, nuts, washers, they cannot be adjusted
(pads height and position is adjustable. Everything else is fixed, unless you consider cutting the extensions to a shorter length adjustment
), they really need to be fit to the rider personally. This means that they are difficult to use for original equipment, and are better suited to aftermarket applications.
Cervelo uses the Base bar and clip ons for one simple reason, you can alter the stem length, bar width or clip on length. When a bike company sells a complete bike to a shop, they can only approximately estimate the proper fit for the final customer. So, in order to allow for the most adjustability, Cervelo opted to use modular components. This allows the shop selling the bike to make the final fit.
As to the pro’s and con’s;
Modular
(Clip On, Base bar, stem
)
• Adjustable
• Lightweight
(slightly lighter than the integrated
)
• Internally routed for brakes and shifters
• Fast
• All angles are adjustable
• A bit more hardware to maintain
Integrated
(Trimax Carbon or Alloy
)
• 4 sizes to fit almost all
• Lightweight
• Faster/more aerodynamic than the modular components
• Internally routed for brakes and shifters
• Minimal hardware to maintain
• Extension angle not adjustable
I realize that most of the pro’s are the same between the two, since the features on both are similar. The key info is the adjustability of the modular set up versus the aero profile of the integrated bar.""
So, there you have it...