Does the 2015 Audi S3 have a timing belt or chain?

The 2015 Audi S3 comes standard with a timing chain on the engine to keep the timing gears synced together. This is better than a timing belt because it does not need to be replaced like a belt. A timing belt usually needs to be replaced every 60,000 to 100,000 miles and is the most expensive regular maintenance item that You will encounter. A chain luckily will last over 300,000 miles. You should still make sure to check Your chain though every year at a service to make sure that there is no damage and that it is not loose. You should also change Your water pump about every 100,000 miles and that is in the timing assembly.