They actually dont look much bigger. Hydor has also released the new Controlable Power heads where you can adjust the flow.

Koralia C Nano 100-260 gph
C 1 180-450 gph
C 2 150-680 gph
C 3 370-950 gph
C 4 550-440 gph

Also Hydor has a new Wavemaker system to use with these.