shouldnt have much of a difference which way round the wires are, as either phase will work adequately, its most likely the fact something in there is rattling (starlet interiors arent designed for big audio installations), so something in there is probably just rattling away. either that, or the speakers themselves are supposed to be amplified externally, the 15wrms from your head unit isn't enough to power less sensitive speakers than the stock items (aftermarket ones might be more powerful, but they're FAR less sensitive, meaning it takes more power to physically get them moving and to sound as good as the stock ones, but given the appropriate power they will obviously be capable of alot more, with the correct secure mounting). but alas, our tinboxes dont help out in that respect