I put mine as suggested by the instructions, in front of the battery. Helps to remove the battery hold-down and move the battery out of the way. Secure the overflow to the radiator support with the two black brackets and zip ties, run the supplied rubber hose from radiator to overflow. Then put the battery back in place. Has been working fine that way so far. If needed I'll take a picture tomorrow, if someone doesn't beat me to it. Won't be able to do it until I get home from work.
Nice place to put it because it's out of view, so people won't immediately notice that you have an extra overflow. Really the only obvious thing about the alky kit is the line running to the nozzle, othewise everything else is tucked out of view.