Light wheels are nice, but your aren't going to feel any difference by going from a heavy wheel set to a slightly less heavy wheelset.

An IRO wheelset isn't going to be much lighter than your present wheels. They both are way over 2000 gms, which, by modern standards, are extremely heavy wheels. You aren't going to find a cheap track wheelset thats very light..its just not a priority for most people riding FG/SS.

For a couple of hundred dollars, you can build a much lighter wheelset than you can buy without using expensive weight-weenie components. Start with a road front hub, rather than a heavy track hub. That will take off at least 100gms, likely more. Use butted spokes, 20-28 in front and 24-32 in the rear (depending on your weight) and a Kinlin rim (depth of your choice, again depending on your weight and spoke count) will get you down to 1350-1500 gms (depending on spoke count and rim depth).

The weights of my various wheelsets vary by several pounds. I can't really feel the difference between any of them when riding along. Are you sure its not all in your head?