the 09 felt isn't that light; my guess is the wheelset is the culprit. my 07 is noticeably lighter than the 09. i'd rather have omniums than 75s for the track, but then again i'd prefer ellipses over the felt's wheelset. in both instances you'll likely replace the post, saddle, and stem.
concept's tubing does feel a little bit thinner, but not as thin as the old track pro.