I know the feeling I just picked up a 2012 after a few seasons off. I sold my K8 orange and black and regretted it everyday until this past Thursday.
Same issue with mine, trying to burn old fuel through it. It runs good at speed but a little rough at idle. Right now stock except ECU flash by previous owner. Picked it up with 2100 miles on it. Starts rough but I'm not sure if the regulator that has the recall or if the battery needs to be replaced.
Will keep it mainly stock with a few modest upgrades nothing too crazy.