well i used rainX just for my side mirror only. works perfectly . but you must apply every time you wash your car.

don't use on your main windscreen. will screw up your wiper. ! "cause mine already cacat "

well there is another type of sticker . saw it in eneons that day. apply on the mirror and it will reduce glare as well as smoother surface allow water drops to slips through easily

hope that helps .