Tom,
The new IMF main sail with the batten is a nice improvement over the  
standard, non battened sail. It does give me additional speed, although only  
slightly, but it does help. It seems as though I am getting more forward thrust  from 
the sail and of course, the additional square footage helps.
Furling and unfurling aren't affected in any manner. You simply take the  old 
sail off of the furling drum and replace it with the new sail. Same hardware  
and no new holes. It's a perfect match.
I highly recommend the new sail. It certainly draws a lot of attention from  
other sailors.
 
Rummy