Which among the following Trek road bikes!!

Hello there,

I am new to road biking and I am on a search for my first road bike. Since I am a Trek fan (owing 2 other Trek MTB and really love them) I would like your comments on the following Trek road bikes that I can find on a good deal. I won’t be doing any racing, but mostly comfortable rides with friends.

Trek Madone 2.3 (2014)
This has alum frame with the Kammtail Virtual Foil tube and with 105 components. This is the cheapest among my options. Sells for 1300 Euros

Trek Madone 3.5 (2013)
This I can get at the discounted price of 1400 Euros since it’s a 2013 model, it’s a full carbon frame and forks with Ultegra components but not the Kammtail Virtual Foil tubes and not internal cabling. Although has some really good reviews.

Trek Madone 4.5 (2014)
This is the bike I would really like to buy but it’s a bit out of my budget. It sells for 2300 Euros.

Trek Domane 4.3 (2014)
This is the Domane model with Iso Speed, It has the Endurance fit and geometry, integrated chain keeper, 400 series OCLV carbon etc . This is on a special price of 1.599 Euros – 2014 model. Since I will not be riding much on “Tour of Flanders” type of roads I am not sure if it would suit me.

I did also a bit of research on Cannondale CAAD8 and CAAD10 models but I believe that in 2015 the new models will come with a new re-designed frame, the current one is from 2011, so why buying one now?

Thanks!!