Hello, I want to sell my BMW. A chip tuning has already been done on this one. This was done on the control unit itself and nothing else was installed. Also a downpipe was installed. Nothing of this is registered. I would like to inform the dealer before the sale about the conversions. Is it enough if one holds these in the purchase contract, so that I can no longer adhere to it afterwards? Or do I have to undo the conversions in order to later no problems Thank you very much for your help! Sincerely