Capacitors?

[BrianG]

You can use as many as you want. However, the more you add, the more "spark" you'll get when you hook up your battery pack. Also, it may be tough to mount/solder them as close to the ESC as they should be.

Yes, you CAN wire them wrong. There should be a white stripe on one side (maybe even have a minus sign in the stripe). This is the negative lead. If you wire it backwards, it will puff/smoke/pop.

Wiring caps in series will add their voltage ratings, but reduce capacitance: Ctotal = 1 / ( 1/C1 + 1/C2 + 1/C3 + 1/Cn)

Wiring caps in parallel will add their capacitance, the voltage will be the same as the lowest one: Ctotal = C1 + C2 + C3 + Cn