You are forgetting that it's not just about outright power... it's about many other things. The R34GTT has vast developments in the engine (hence being badged the NEO), the turbine system (bigger than R33), the suspension, the brakes etc etc. Even the HICAS system in the R34GTT is vastly different to that on the R33GTST.
I think if you compare the facts; the power difference is noticeable but more so the torque. The NEO's VVT system is much more developed than that on the R33GTST I'm afraid.