I used to have a pc3 and the white plastic piece with the two wires coming out of it in the OP looks like the 9v adapter. It's only needed when programming the pc3, not needed for everyday running of the bike.
Selling my used Yamaha Gel seat for $110 plus actual shipping costs. Seat is in great condition. Previous owner put some scuff marks on seat surface but nothing significant, and no tears or rips. Noticeably more comfortable than stock seat. Comes with hardware so you don't have to take apart...