Like I said, your comment initiated it. Accurate information was provided. You disagree with it and pretty well told them they don't know what they are talking about so go and google it.
With a comment that can be taken in that way, I expected something to be said. If you did not, I can't understand why you would say that. Nonetheless, I'm not here to sort out the personal stuff.
As far as the discussion goes, it seems to me it's quite clear it concerns brushless setups. You can determine this quite easily by the characteristics / information provided in the original post. The second post confirms this.
Saying this:
From what i understanded he was saying people installed Caps to audio system on the sole pursose to help power the sub.
and then saying this:
Where i belive its to save the alternator from excessice voltage spikes and to stop ur lights from dimming,.
Is saying the exact same thing. All you have done is looked at it from a different perspective. The charging circuit is the exact same circuit that the amp/sub is connected to so of course it will include everything else that is attached to it. Voltage sags in any component is very bad. It concerns me greatly when I see systems making lights dim to a very high level. The ECU or ECM to some, is also connected to the charging circuit and effected by voltage differences.
For the exact same reason he has said, we do not desire voltage fluctuations in our ESC. Capacitors will help out. However, when there are severe fluctuations it can destroy the caps and once the caps are gone or weak, the ESC may fail.
This is why I highly recommend a 2p setup on demanding systems, as it increases reliability for this and just about everything else without the need to add caps.