Florianz, yes, caps make a difference, but it's not the size that counts, it's the low esr (equivalent series resistance) values that help the esc. That's why I have the cap bank right inside the case, soldered directly onto the board with a heavy buss bar. I would love to have some solid polymer caps to use on it, very low esr and small, and very durable.
My last Quark I modified,
HERE, worked wonderfully, rarely cogged even geared to the moon, and ran super cold (most likely due to the heatsink it sat on, which actually increased to value of copper world wide when I put it in there, lol). It was too heavy, and was eventually killed because of physical damage from a hard crash.