Long story short I kerbed my 2015 Audi S5 Sportback and it has totalled the rack, I have had a mechanic check it over and the fault codes relate to a failed rack. So question is my part number for the rack on my vehicle is 8K2 423 055 BY, I can find plenty of replacements online however none with the same letters at the end ‘BY’. Do the letters need to match for they replacement rack ? Thanks in advance