The advantage of parrellal is longer run time. If you run two 7.2volt 3800 packs you get 7.2 volts at 7600 mah.
The advantages of series is two 7.2volt 3800 packs you get 14.4 volts and 3800 mah.
You don't accually need the plug close to the esc either. That part is optional.

I have a question on mounting my controller. right now i set it up right next to the motor, where the other stock is to be. My wires were not long enough to run from the back. that's where i'm going to put my ubec though ( in the back ). But the wires are gonna be real close to the antenna. is this going to interfere with reception at all?

it shouldnt.

thanks squee. when i am able to these pics on, i want you guys to see my mod job on the other motor mount side to mount my controller. i used a body mount for it!!! i turned out cool. the controller will be next to the motor