The “noughties” brought us many exciting and capable cars with future classic potential. Some, like the BMW E46 M3 get all the attention, but the other German premium sedans were still good. No, we are not talking about Mercedes C55 AMG, which is also a fantastic German muscle car but Audi, the third member of the Teutonic power trio with its legendary RS4 model. Heres why you need one in your life.

Difference between S4 and RS4

Right from the start, we should explain the difference between the S4 and RS4 since these two models are visually almost identical, have the same displacement engine, and similar Quattro drivetrains. However, those two cars are not the same, and the RS4 is considerably faster and rarer. The Audi S4 B6 was introduced in 2003 and featured an all-new 4.2-liter V8 engine with 344 HP on tap. It was the top of the line A4 model, and when Audi introduced the restyled next-generation model in 2005, called the B7, the S4 continued in slightly newer body but with the same components, layout, and power output.

However, Audi knew that the B7 platform, Quattro drive train, and fantastic high-revving V8 had more potential, so in 2006, the RS4 was introduced. Apart from the new front and rear bumper, slightly bigger wheel arches, and discrete RS4 badges, it looked the same as the S4, but the real difference was underneath the body. The 40-valve 4.2-liter V8 now had 420 HP, and 317 lb-ft (420 Nm) of torque and the Torsen Quattro all-wheel-drive system was re-engineered to have 40/60 split between the axles. The only transmission option was a precise 6-speed manual; brakes were bigger on all four corners, and the suspension was revised. Although the regular S4 was no slouch in terms of performance, the new RS4 was a different beast.

Performance

The official Audi`s press release from early 2006 states that the new RS4 had a 0 to 60 mph time of 4.8 seconds and an electronically limited top speed of 155 mph. However, this is a prime example of Audi`s signature deliberate conservatism when declaring performance figures. Most independent testers achieved 0 to 60 mph times of 4.4 to 4.5 seconds and reported that the electronic limiter is rather “liberal” since the top speed of almost 170 mph is achievable. It was pretty apparent that RS4 B7 is really a proper German hot rod, dressed in a three-piece suit.

Interestingly, the engine from RS4 B7 was used in the first-generation Audi R8 supercar without any changes. Since the capable Quattro all-wheel-drive system was performance calibrated and rear-axle-biased, the RS4 B7 was capable of smoky burnouts and power slides. However, the intelligent AWD system gave this model incredible real-world stability in all driving conditions and a significant grip advantage over BMW or Mercedes competitors, which had just rear-wheel-drive layouts.

Potential Problems

The Audi S4 B6/7 had a notable problem with the timing chain on its version of the 4.2-liter V8 engine. The problem was that the plastic tensioners which hold the timing chain get worn and caused the chain to rattle and loosen over time. Ultimately the timing chain can fail and cause fatal engine failure. The servicing proved to be very difficult since the timing chain assembly was not in the front of the engine as with the most cars but the back, close to the firewall. Audi engineers realized the problem, and the RS4 version of the engine featured tensioners made of metal with plastic lining, which somewhat solved the problem. Still, pay good attention since the replacement is expensive.

The problems unique to the RS4 are failing injectors, failing first and second gear synchros, and Dynamic-Ride Control handling system. All of those things you can quickly see when you go to inspect a potential purchase. If the car has a rough idle, blue or white smoke, grinding transmission, or sits too low, walk away.

Production

In just around two years of production, Audi managed to sell 10,000 examples in three body styles. First, the saloon version debuted, followed by the station wagon, and in 2007, Audi presented the RS4 convertible. The sedan and wagon are most common, but you can find convertibles as well. If we might suggest, stay away from convertibles since many journalists criticized its lack of torsional rigidity, which affected excellent handling of sedan or station wagon.

The prices

When it was new, some 13 years ago, the Audi RS4 B7 cost around £60,000, which is approximately £85,000 in 2019, adjusted for inflation. Yes, it was a pretty expensive machine, and rare as well since only about 6000 examples stayed in Europe. However, the RS4 B7 is now finally obtainable by average performance car enthusiasts, with prices starting at around £15000 for high-mileage examples.

If you’re shopping for a used performance car, never buy the cheapest one since its probably a disaster waiting to happen. Always go for full-service history, low mileage ones with no crash damage, or cheap modifications. In the case of the RS4 B7, those examples start around £20,000, and for £25,000+, you can get the best of the best. For us, this is a no brainer since having a supercar-powered sedan for the price of the family hatchback is a dream come true.