You could also run into trouble with trail. Traditional steel frame forks tend to have more trail than most carbon forks, so if you are not careful in fork selection, the wheel may end up too close to frame or even hit it. It's also possible that the bike may weave at high speed as the frame was designed with a particular amount of trail and you have reduced it.
Personally I would continue to use the forks that the bike came with. The improvement will be negible compared with what improving your fitness will acheive.
