Sent an email Tony.

Yes, the ones in the DeWalts are the ANR26650 cells (26mm diameter, 65mm long). These are the only cells that A123 currently produce. The larger cells (M1 HD and M1 Ultra) are not in production yet.

The A123 cells do seem to perform slightly better when warm, but apparently they still suffer a reduction in life if they go over 60 deg C.

The main reason to balance the cells is so that we can use simple chargers at competitions - so we dont have to fiddle around connecting all the balance wires every time they need to be charged. Also cheaper.