ICC10 is calibrated around being completable by people in no higher than ToC10 gear. Some of the ICC5man stuff is a lower iLvl, but better itemized, and therefore superior. Combined with the 245 off-sets you can pick up from emblems, as well as 264/251 emblem gear, it's rather easy to step into ICC10. Basically, if your average item level is between 230 and 235, you'll be perfectly suited for ICC10 and receive quality upgrades from the instance.