Recommend me the correct valves and drop a link where i can purchase please
 

Hi i have an audi a6 c5 2000 aha motor code can provide vin if thatd help. But i need to know the correct valves to buy as there are a variety and the ones i i found on rock auto idk if they are the right size. Please if you have a link available where i can purchase the CORRECT SIZE please please please provide it for me. Thank you.