Ways to protect MMM when used with subpar batts

This thread has been very informative, and I'm glad it turned into a healthy discussion.

Update - I borrowed a 4s pack to try and found that the car was just too fast for the indoor track with it. So, I picked up a 3s Zippy (25C 5000) for <$50 and it seems to work quite well. I figure the lower voltage will reduce the amp draw, voltage stress, ripple, etc., and be safe to use. (?) I've kept the gearing and ESC settings the same so far, and I get about 25 mins. runtime until 3.5V/cell LVC kicks in. The motor and ESC come off just warm, and the pack a step above stone cold. I am slower on the straight than the 4s guys, but not by that much, and from the looks of it, I should even be able to go up some on the pinion for a bit more speed. Other than that, the tame setup and budget battery seem to be fine together. Do I still need to add more capacitors?