I love this one. Just put the metal square on the inside of you case or on the inside of the back cover and your good.
http://www.logitech.com/en-us/product/plus-drive
It's like a different phone. No lag, no heat issues. Like I said only had it for a couple of days before the update, it got warm before but nothing after the update. As far as signal my nexus 6 got a little better signal then the flex 2 nut the nexus is a signal beast.
No Framily upgrades at Best Buy, Sprint took that away. You might have been able to preorder but when you go in you will have to switch to one of the new plans. Only Sprint Corp stores can touch Framily. Even if you do easy pay, doesn't make sense, I have Framily can't do anything at my Best Buy.