How hilly are your roads? I'd give the Fairdale a little more consideration if your roads were basically flat, allowing you to swap out that 11-40 cassette with something more road oriented (like a 12-27). Given that you want to ride hard (looking for a 2-3mph increase) and may do some group rides, that 11-40 cassette is going to become a hindrance sooner or later. With any decent hills in the area you will want lower than a 42/27 combo, though.

Your Trek likely has a 48/38/28 crank and 11-32 cassette. How much of that gearing range do you consistently use now? If you never shift out of the middle ring now perhaps the Fairdale and a slightly tighter spaced cassette will work for you.