Disklavier

Hi, need a bit more help, please!!! Was set to purchase a GC1M4 (5'3") 
as I am not a player, its in my price range and am really buying for 
disklavier which I love. After listening to my friend play the same 
pieces on both the GC1 and the C2 (5'8") side by side I could hear a 
difference, not huge, but noticeably smoother. The larger C2 will fit 
in my apartment and is about $10,000 more. Now I understand the 
disklavier on the C3 is different from the unit on the GC1 and the C2 
in that it has hammer sensors. Can anyone offer some advice? Do the 
hammer sensors affect playback of pre-recorded software or just 
recording. If only recording then no matter since I can't play anyway! 
Buying a car was much easier. Thanks,
Ron