Power cord construction techniques

Hi.

I've started down the path of building my own power cords. I'm starting with Belden 83803 (thanks Subaruguru) and Marinco ends (PartsExpress). After finishing my first cord and trying it out I decided to take off the ends of two of my specialty cords (shall remain nameless for now) and seeing how they were made. I was a little more than surprised at what I found...

1) Both cords used two wires for the neutral hookup. Hence there are four wires total in each cord.

2) One cord has a capacitor wired across the hot and neutral terminals. My initial investigation says it's a 125L Vishay capacitor designed for EMI reduction.

My questions, if they aren't obvious, are what are the benefits of 1) and 2) and should I be doing this too?

Thanks!

leo.