true on both notes. The higher mah and lower IR packs will have a higher voltage at the end of a given period of time with the same load. I compared my 1 year old gens ace 5k 40c to my 4100 shorty 65c and after 5 minute @15amp discharge, the 40c gens ace had a higher ave voltage. Now, the heavier pack will also use more mah. But i am convinced a good 5k 300 gram pack with a low IR would have more power than my shorties over the course of a race. not would going to 7200 mah 70c be better with the added weight? dunno.