34 has a stiffer chassis too, even stiffer than an r33 gtr i think (happy for someone with more knowledge to either confirm or dispute this though, as I can't remember where i read it).
Plus, in my view more important than the differrence in KW is the better low-end torque of the NEO engine, 343nm@3200rpm vs. 295NM@4800RPM for the 33. This, and the better quality interior, is why most people say its a more refined ride than a 33.