The Rho complex pic I posted recently had no ICNR and was a stack of 20 10minute subs at iso1600.
http://s231.photobucket.com/albums/e...t=RhoLarge.jpg
Turned out not too badly - I expected loads and loads of noise, but I only applied very minimal NR with the Noise Ninja plug-in which had only a subtle effect.
Noise (and the lack of it) confuses me!!!!!