The slightly better specs are nice. Looking at the geometry, specifically Stack and Reach (the top point of the head tube, along its center line), the Sirrus 2.0 is longer and lower across the board than your Sirrus Carbon Sport (assuming 2017 geometry is applicable to yours). Trek FX geometry by and large has remained consistent through the years, and the FX2 is no exception. Compared to your current Specialized and the one you're considering, the Stack/Reach situation is more favorable to you being able to adjust it to your liking. I've long thought/said that you can always 'grow' a bike [taller seatpost, longer stem, etc], but it's really hard to 'shrink' a bike. If you're able to test ride the new Sirrus, that will be immensely helpful. Good luck!