Well I know there are two different M1 cells (albeit small difference), between the original "developer kit" cells and the Dewalt pack cells... the dewalt cells are 2250mah, and the developer kits are 2350mah

They can all do the same discharge rates, and made with very tight tolerances, just a bunch of clones.

On paper or in a controlled test environment?

I haven't done any soldering to A123 cells. A German distributor is stating "direct soldering will damage the cells".

I have done some measurements with the cells and can't imagine they supply 70 A continuous. Even on their data sheet they don't show a discharge curve for 70 A, not even 60 A or 50 A: http://a123systems.textdriven.com/pr...APRIL_2009.pdf

Not true. You do need to use a minimum 60W iron with a heavy tip on it to hold lots of heat because that allows for a very fast joint. The cells don't get hot using this method. If you try to use a plain tip iron, or a low wattage iron then you will have to hold it to the cell longer and it may overheat and be damaged.

I have direct soldered all my packs with no performance or perceivable cycle life decrease. I use a 300watt iron to solder them.