The B9 Audi S4 is an easy car to service when it comes to the engine filter. It shouldn't take more than a few minutes to swap yours with hand tools. The carbon air filter on the other hand was a bit of a pain just due to the cramped conditions. Overall give yourself at least 20 minutes for a first time swap of both filters. Once you are familiar with the process you'll be doing both in minutes.

The following OEM filters are highly recommended:

Audi Engine Air Filter (8W0133843) - https://bit.ly/8W0133843
Audi Cabin Filter (4M0819439B) - https://bit.ly/4M0819439B

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