Adding information to the thread.
I live in Seoul and 2015 Ford Explorer Limited owner.
Many of the Ex users in Korea have installed the auto power step.
I have got lots of informations from the explorer forum so I would like to share my info to you as well.
As far as I know, there are two companies who makes the auto power step, Autostep and Broszen.
Here's the link for two companies.
Auto step:
http://www.autostep.net
Broszen:
http://btypenine.wix.com/broszen
link to the videos:
https://www.google.co.kr/#q=익스플로러+브로스젠+
From what I've heard, the engineers at the Auto step had some problems with the owner so they quit their job and found a company called Broszen.
For the functional wise they are pretty much similar and they work with Ex remote keys.
The price range is around $1500~1700. I think the installation fee is included in the price.
If the quote you've got includes shipping, I think the price isn't so bad. But if not, I think you need to consider the shipping cost.
From what people blog about, there seems not that many issues with the power steps but some have problems with the LEDs installed on the auto power step.
What I've heard from a friend yesterday is that there is another company which will be launching auto power step with better safety function.
Let me know if you have any questions.