You will notice a HUGE difference. I bought a Trek 7200 a few years ago to get back into biking. I did what I could to make the 7200 a better road bike... straight bar, new seat, smaller tires, and got rid of the shock fork. It was better, but not very satisfying. As it turns out I got more serious about riding and moved on to a road bike... well, actually now it's two road bikes!

You can do fine on your Trek, but it's not going to be the same experience as on a road bike. I did lots of organized rides of 70-80 miles on the 7200 and it was fine. Not fast, but fine. But with my road bike I routinely do solo rides that far on weekends in MUCH less time, and I'm not tired afterward (well, a little!) You'll go faster, farther and do it with less effort on a road bike. At the end of the day you won't feel like you carried the bike on your back. I now only use my Trek for family rides with my kids, knocking around in town, on rail trails, or when I need to carry things in a trunk rack or panniers. if you're like me, you won't regret getting a good road bike. I say go for it!