Essentially more practical versions of sports sedans, performance wagons combine all the benefits of a practical family hauler you can daily drive with the kind of performance usually reserved for all-out sports cars. Because they blend into everyday traffic so well and secretly boast serious performance, performance wagons usually make the best sleepers, too.In 2026, these would be your BMW M3 or M5 Touring, Porsche Taycan Cross Turismo, and Audi RS6 – all of which have one common denominator: a steep price tag. However, hiding on the used market is a wagon that would put all of them to shame with its massive engine and understated looks, and despite that, it's an absolute bargain any gearhead can afford. It's a rare example of a compact performance wagon of its kind being sold in North America. It was also one of the first cars to have an engine that has now become legendary. On top of that, it's actually a pretty good bargain on the used market. The B6 Audi S4 Avant Is An Iconic Modern Performance Wagon Bring A TrailerIf you think of 2000s European performance wagons, one of the cars that'll pop into your mind is the B6 Audi S4 Avant. It was one of the best practical performance cars of its era, easily holding a candle to anything BMW or Mercedes could throw at it. It had all the things people have come to expect from a high-performance Audi. It's fast, comfortable, its engine sounds great, and it's easy to drive thanks to its quattro all-wheel drive system. That estate trunk also makes it incredibly practical – it's got a capacity of 442 liters with the seats up, and a cavernous 1,184 liters with the seats down.Bring A TrailerOne of the things that makes the B6 S4 Avant iconic is that it was the first S4 Avant to come with a V8. This 4.2-liter V8 replaced the old 2.7-liter twin-turbo V6 that powered the B5 S4. It was significantly more powerful than the old V6, having 339 hp as opposed to the 261 hp of European-spec B5s and 250 hp of North American-spec B5s. It was also more powerful than the legendary Audi RS2 Avant, which has 315 hp. That big power, combined with the glorious sound of a naturally aspirated V8, quickly made it a firm favorite in performance wagon circles. It's An Absolute Bargain On The Used MarketBring A TrailerEuropean performance sedans and wagons tend to depreciate into serious bargains over time. That's no different with the B6 Audi S4. Across all its variants, the B6 S4 is worth just around $13,950 today. The Avant models tend to sell on the higher end of that average.Of course, the same goes for manual transmission models, which are currently significantly more desirable than automatics. While autos trade in the low teens, for example, manuals fetch closer to $20k or more. One manual transmission example from 2004 recently sold for $20,750 on Bring A Trailer. This wasn't that much of a garage queen either, as it had covered 161,000 miles around the time it was sold. Manual Transmission B6 S4 Avants Are Guaranteed Future Classics Bring A Trailer Keep in mind, S4 (B6) Avants are exceedingly rare performance cars, which further drives their future value potential. There are no clear production numbers for the entire run, which is estimated to be in the low thousands according to forum AudiZine. According to posters, B6 S4s are also an extremely rare sight on American roads in general. That not only makes this powerful and practical performance wagon a great bargain on the used market, but it's also one that looks like it could appreciate in value over time.The B6 S4’s glorious V8 does come with known ownership considerations, most notably its rear-mounted timing chains. While many cars run well past 150,000 miles without issue, repairs can be expensive if neglected, often requiring engine removal. Fuel economy is also firmly in the “enthusiast tax” category. For buyers who prioritize sound, character, and rarity over running costs, these trade-offs are part of the appeal. The Audi S4 Was Also Available As A Sedan And A Convertible BaTWe're focusing specifically on the Avant here. But it's worth remembering that the B6 Audi S4 was available in multiple body styles. This included the sedan model and the rarer and lesser-known convertible. Both models used exactly the same platform and powertrain as the Avant, and therefore had similar performance, with the convertible being a bit heavier. Sharing An Engine With A Supercar AudiOne of the prime selling points of the B6 Audi S4 when it was launched was that brilliant 4.2-liter V8 engine. Considering that it's a fantastic-sounding, naturally aspirated unit, that's not surprising at all! This engine has now become legendary among Audi enthusiasts, and for good reason. A later development of it ended up powering the first generation of the Audi R8 supercar. The V8 was one of two engine options, the other being the 5.2-liter V10 that later became the only engine option after the R8 moved into its second generation. While it was the less powerful engine option in the R8, there are some enthusiasts who genuinely prefer it over the V10. Later S4s and RS4s Also Used This Engine Via: AudiThe B6 wasn't the only generation of the S4 to use the 4.2-liter V8, either. The later B7 model also used it, as did the more powerful RS4. When the B8 generation of the A4 was launched, the S4 changed to using a 3-liter supercharged V6. But, the B8 RS4 kept the 4.2-liter V8 going for one more generation before scaling down to a 2.9-liter twin-turbocharged V6 for the B9. While those cars may not have the supercar credentials of the R8, they are all still beloved by Audi enthusiasts. The Last S4 Avant To Be Widely Imported To America Bring A TrailerOne of the main reasons why the B6 Audi S4 Avant is such an icon is that, in North America, there wasn't another car that replaced it in Audi's model line-up. It was the last S4 Avant to be widely imported stateside. Customers on the other side of the Atlantic did get Avant versions of future S4 generations. But, for whatever reason, Audi just didn't think it was worth trying to sell them to American customers. That's a real shame, especially considering the B7 S4 Avant was arguably even better than the B6 version.Sources: Audi, AudiZine, Bring A Trailer, Classic.com