Purchasing a used Audi S4 can be a very rewarding experience, but it can also be a huge headache if you do not complete the necessary research before selecting your car. The Audi S4 made its first appearance to the U.S. Market in 1999, known as the B5 S4. The B5 S4 packs a twin turbo v6 under the hood and became a staple car in the race for the best German made sedan. Audi imported many B5 S4's to the U.S. until its retirement in 2001, so they are pretty accessible and easy to find on the used car market. After a short break with no S4 in Audi's lineup, the 4.2 liter V8 B6 S4 took over in 2003. With the introduction of the B7 body in 2005, Audi also introduced the B7 S4 to their lineup featuring almost the same exact car as the B6, only with the updated B7 body styling. For 2009 Audi redesigned the S4 after creating the B8 chassis. Due to the recent fuel crisis, Audi downsized the engine to a more fuel efficient V6 but also added a supercharger to ensure the current car has more power than the previous V8. The new B8 S4's are just starting to be imported to the U.S. so you probably won't see them on the used car market until 2010 or 2011.

Now that you have a brief synopsis of Audi's S4 lineup, you will need to establish which body style you like, which engine you prefer and which style will fit your budget. Please take into account that the S4 is considered a higher performance model over the basic A4 in Audi's lineup. With the added performance status, you can expect a more rewarding driving experience, but you also need to expect a higher purchasing price as well as higher maintenance and repair costs. The B5 S4 has a reputation for being especially finicky when it comes to reliability and maintenance. If things do break on the B5 S4, repairs may become expensive as the twin turbo V6 is packed tightly into the engine bay and requires complete removal for some of the common issues known for the car. When it comes to the B6 and B7 S4's (which use the same V8 power plant) the most common issue is coil pack failure. Fortunately, failed coil packs are a fairly simple and inexpensive fix.

If you do choose to purchase a B7 S4, it may still carry the remaining factory warranty which is good for 4 years or 50,000 miles and is transferable. Furthermore, if you would like to have a little more peace of mind, you also have the opportunity to purchase a CPO (Certified Pre Owned) vehicle from an Audi dealership which carries up to a 6 year or 100,000 mile warranty. If you choose this route, expect to pay a higher initial price because you're purchasing from a dealership, as well as a few thousand dollars extra for the CPO warranty. Remember this can save you a lot of money in repair costs down the road.

Finally, as suggested with any other used car purchase, you will want to compare prices with similar cars, check retail book values to see if you are receiving a fair deal and check a free car history report for any signs of previous issues. Once these steps have been completed, make sure you give the vehicle a full visual inspection to look for any imperfections and/or issues that could lead to problems in the future. Once you have found and purchased the perfect car, enjoy your new German-engineered work of rolling art.