Default Samsung S5 wireless back pieces?

Anyone tried them out and what are your thoughts? Does it possibly compromise your IP67 waterproofing? Any options from 3rd parties that are the same thing and waterproof that can be had for less than what Samsung is asking? Any particular charging pad from 3rd parties that you like or would use... and last but not least... Are any of those pads magnetic where they could perhaps hold a phone verticle if the charging platform was mounted? I'm curious about the possibility of using one in car similar to a car mount that doubles as a charger. Thanks.