I converted my Le Tour to fixed a little bit ago, and definitely enjoy the feeling of riding on 700x23's... very fast, very little rolling resistance (they're also pro2's though). the older wheels were definitely heavier, so if you get a newer decently priced wheelset, if you feel like shellling out that is, then you will definitely feel an increase in nimbleness, even if you're riding some fatty 35's. i would recommend dropping to 23's though, personally...