The MobilePal wireless receiver cases are electronically compatible with the built-in wireless chargers in select GM vehicles, such as the GMC Yukon or Cadillac Escalade. For the iPhone 6, it should work without issue. However, for iPhone 6 Plus, the receiver case may or may not work due to size constraints of the charging pad.
The Qi wireless charging pad on some GM vehicles, including the 2015 GMC Yukon and Cadillac Escalade, is too small for iPhone 6 Plus, so the iPhone 6 Plus cannot lay flat inside the tray of the charging pad, causing wireless charging to fail. However, some customers have reported that wireless charging works well after they removed the rubber pad on the charger to allow the iPhone 6 Plus to fit. Hopefully GM (or a third party) will introduce a more permanent solution in the future by making the overall charging tray larger.