Different topic: how to kill Sylar
Note that Parkman can still identify him, and Hiro could kill him pretty easily. Also if Peter got some version of his father's ability locked inside somewhere, he could also kill him the way Adam Monroe was killed.
Other ways to kill Sylar: the Hatian + Ando could probably shut him down, then just shove a spike into his brainstem and bury him in a few hundred feet of concrete.
Baby Touch n' Go might be able to stop all his powers. I would love to see a scene where Sylar tries to make the baby happy in order to get his powers back.
If they came up with someone who had sonic powers they might be able to hurt him pretty bad, maybe mess up his shapeshifting and other powers.
There was that one guy who could open portals to another dimension and disappear objects, they could do a variation on that.
If they came up with a poison ivy type character that could enslave him via lust, it would be pretty easy to kill him.
So he's not uber-powerful yet, just too powerful to handle in any conventional sense. He's reached the point now where ordinary mortals couldn't stop him. Even the army would have a hard time with him, at this point.