Yes, but with the cheaper KH310 with 2 KH750 dsp- subwoofers theres gonna be two advantages:
1. Two KH310+ 2 KH750 dsp becomes a 4 way loudspeaker , meaning less frequencies for each driver to play. The result will be less IMD distortion with complex music , if the quality of the amplifiers and drivers are of the same high quality. A good 4 way loudspeaker has less compromises in the crossover regions than a good three way , if done right.
2. The Neumann subs have room-correction and thats a big advantage below 80 Hz , to compensate for the walls in the listening room. The KH420 dont have this.
3. The KH310 + 2 KH750 dsp might because of this have a better sound than two KH420.
One has to compare the sound quality carefully and with real music.