I have a 2013 Domane P1, which I love.
The Domane disc bikes look great, but I really think that Trek blew it with only two options.
Who wants a Sora equipped bike?
I'm sure that Sora works fine, but c'mon Trek, nine-speed & exposed cable housings?
We're at 11-speed on most new bikes, 9 is a step backwards.
The 4.0 has Tiagra 10-speed (along with the exposed cables), but at least it's 10-speed.
The 4.3, at only $100 more, has 105 10-speed.
Trek should have offered a 10-speed disc option at ~ $2300.
The Sora 9-speed was a major mistake.