Not sure, but I think Corbin doesn't use your existing seat pan.
http://www.topsellerie.co.uk/KAWASAKI-GTR-1400-seats-petrol-tank-covers-tank-bags-motorbike_6_451.html
Corbin makes their own pans so no sending in the stock seat. I don't think it lowers it. Been so long I can't remember what the stock seat is like.
Interesting. (Although one of the most annoying sites ever.)
Ended up ordering the Kawasaki Touring Seat from PowerSportsWarehouse.com back on the 21st... $455.
Finally got my Kawasaki Tourning seat today, haven't ridden it yet but I will later today. Had to deal with some hassles to get it, but it is here nonetheless.
Let us know what you think of the touring seat. I have a 2015 and was thinking of getting that in hopes it was softer than the stock one.If your bike is a 2015 you have the Touring seat!