We're not talking about Trek. Which are you talking about/
I have a Foil and have never ridden a Venge, so am half qualified to have an opinion. I have also briefly ridden a 2013 7.9 Trek. The foil is now for sale and I have ordered the Trek.
If you buy into to aero advantage thing - and let's suppose we do, then do yourself a favour and try this thing. Riding the Trek is like riding a magic carpet over clouds compared to the ass slapping the Foil gives you over any imperfection.
Is it as stiff? Sure, I guess. As aero? No idea... But it would probably be close. As light? Lighter by all reports. As comfortable? Miles and miles ahead of the Scott.
I am 6'4 race B grade in Aus. Ride on flats fast, up hills slower, and ride anywhere from 1 hour to 5 hours at a time.
If I were you I would at least consider investigating the Trek.