I emailed NASales about my order. I've confirmed, but was curious about adding the subzero weather package - whether that addition would also incur the $500 change fee. I'm assuming it absolutely would, but just wanted to hear back from them. Does anything have any experience with this? I haven't had a response in days. It's not a huge deal; I just got to thinking about road trips where I was trying to stretch range. Once my kids are out of boosters (and one of them is close), it would be nice to heat their seats as well and use less cabin climate control.