I require a replacement steering rack and have been offered a reconditioned of another a5,the problem i have is that the part numbers almost match except the last letter,my car is 8T2422066C but the one ive been offered is 8T2422066B, does anyone know what the difference would be and would this be compatible???

 

I believe the version in your car is the revised version. I believe when they do an update on the part they change the letter. Hypothetically it should fit. Also bare in mind it might need coding to the car. 

Hello Brian,

Thanks for being in touch with the forum. There has been previous debate about the significance of the last letter, and I believe it can be rightly claimed that the last letter only signifies a later edition of the same part. 
This isn’t going to answer your question, ‘later edition’ may mean yes it’s identical, or yes it’s the same part, but there are subtle modifications - which may or may not matter. On the ‘may matter’ front, you could find electrical connections have changed etc. (just an example).

There is another school of thought that indicates that the basic long part number is the generic number for all such components - e.g. cambelt kits - and the last letter is indeed meaningful, and signifies different kits for different engines. 
Apologies for not answering your question, but it may mean you have to suck it and see, if you have the option to return it at you cost, if it turns out not to be a suitable fit. 
Kind regards,

Gareth.