taller thinner tire will def make the turn in feel sharper and easier (less rubber contact) i went to a taller fatter one and the opposite was true. As for the other thing, hard to say, if both tires were done it could be either something is out of balance on the front, the rear could be out of alignment with the front, it could simply be a weight issue on the front rim, could be a bad tire, did you have any other work done to it at the time when the tires were replaced?