i have the fix for you!! i bought an ebay tcu that had all the proper # and when i installed it guess what ? limp mode!! turns out many tcu's are the same but the files installed are different for the car its used on. in my instance i needed the slk32 file and the tcu was programmed for the slk320. sooo off to speedriven the tcu went and marcin flashed the proper files onto the tcu for 100$. total cost for the tcu to work properly was 235$ shipped and new the cost was 883$!!!
so get the proper tcu and ship it to marcin and you can save hundreds