I purchased this from someone in a Facebook group recently but it did not work for me (I'm too light at 150lb), so I'm going back to stock.

The seat is used but was purchased last year and has one riding season on it.

Asking $575 + shipping (probably ~$35 shipped in the USA). PayPal or Venmo ...

I don't have any experience with the later ABS systems used on your bike, but that sounds more like a computer problem or the wiring to it.

Are the brake lever/pedal switches working properly?