Have a used PC3 USB for RC51 for sale.
Currently has a custom dynoed map for open airbox and Sato Banzai s/o exhaust. I'll try and post a pic later but if you're looking for one then you know what they look like.
$225 shipped in 48 states.
Please do not let the newbie post count scare ya, been a RC owner for years and have a respectable reputation on a couple RC sites.