In stock form, this 2.4L blower is running 14,600rpm at rated power and 11.4-11.5psi. So it's definitely not at it's max rpm or psi. The Z06 is running a 1.9L blower spinning 20,000 at rated stock power, so it's doubtful that they'll be able to squeeze much more out of that one. But the Hellcat blower definitely has some more in it.
Still, the big gains will be made when Whipple or Kenne Bell come out with some 3.0-4.0L blowers for these cars. That'll probably be a while though...