It should be a little lower than that, around 25ms or so.
Let's put it this way - you cannot currently buy a faster TV to game on (all the 2011 Panasonic plasmas seem to have the same lag). If 25ms is too much for you, then your options are awfully limited.
I had a GT30 and the lag was pretty fantastic. If you need better, you might have to hunt down an older Sharp LCD with Vyper Drive. They reach 16ms, but the new ones suck badly.