Good questions... I'm not sure I know the answer but I am not aware of any limitations on upgrading generic software on any 188E. I am almost positive that I have put V4 software in a KY4 board so I don't think you will have a problem getting the same software working in all 3 cars if you upgrade just 1 188E. I would try to replace the 1 188e and put V4R5D in all 3 cars. Are they selling you a KY9 or KY11?
