Everywhere you can. Your e.s.c., battery packs, charger. They replace the white bulky tamiya/standard plugs you have on all of your stuff. Also I should warn you not to switch over if you charge battery packs for a rotostart, ez-start or anything where the connector cannot be changed, unless you have a spare charger for those.

EDIT: If you're handy with a soldering iron you can make use of your skills by cutting out some of the slack and cleaning up that way. Also effective is wrapping the wires around a screwdriver in a circular fashion to shorten them, it will give them a curley-Q.