I've got a V3 Sprint Booster for sale. Comes with original box. No instructions but they can be downloaded online. Works perfectly. I superglued 2 small, thin magnets on the backside of the controller and I had another small magnet double sided taped to my center console so I didn't have to permanently mount the controller. You can see that in the attached pics.
Edit: all the pictures uploaded sideways but you get the idea what it looks like.
$175.00 shipped anywhere in the US. Paypal fees included also.