I have it listed on eBay for $379.99 with free shipping. You can view it here: http://www.ebay.com/itm/291809559975?item=291809559975&viewitem=&vxp=mtr
Take a look!
Piaggio MP3 500 ABS Gel Comfort Seat - Brown - New OEM
Brown Gel Comfort Seat for Piaggio MP3 500 ABS - 2016 and Newer (2S000137)
This OEM Piaggio Gel Comfort Seat for the 2016 Piaggio MP3 500 ABS and new models is easy to install and a "must have" upgrade for you & your passenger. Perfect for long distance touring or that extended commute.
OEM Part number 2S000137
The seat includes a new protective seat cover.
This accessory is OEM Original Piaggio, sold and packaged by Piaggio, Inc. in Italy. OEM Piaggio parts are the highest quality available for the best fit and finish.
This accessory fits: Piaggio MP3 500 ABS (2016-Current)