The RS4 shows Audi at its brilliant best. Fast, frantic but perfectly practical, this improved version of the fourth generation model remains a Ferrari for families, a five-seater estate that here retains 2.9-litre V6 biturbo power with a 450PS output, but gains a smarter look and a plusher cabin.
Every once in a while, a car is developed that is so good and such a class benchmark that other manufacturers are very wary about taking it on. The Range Rover for example - maybe even the Mazda MX-5. Audi makes such a car too - and it's this one, the RS4 Avant. If you want a very, very fast, four-wheel drive estate with supercar performance, there's really no credible rival to this one. The work of Audi Sport, the Ingolstadt brand's go-faster arm, the genes of this particular car can be traced right back to quattro's first product, the RS2 estate that was co-developed with Porsche in 1994. It paved the way for the first generation in the RS4 line, the 2.7-litre twin-turbo MK1 model of 2000, ferociously quick but ultimately rather unsatisfying in the way that very fast Audis used to be. But aren't any more. The second generation RS4 of 2006, this car, proved to be a landmark car for the brand, a machine good enough at last to properly challenge the all-conquering BMW M3. The third generation version of 2012 used the same 4.2-litre V8 and continued that trend, But can the same form line be maintained with the switch to V6 power? Let's find out.
The 450PS 2.9-litre TFSI biturbo engine is just as before, powering this car to 62mph from rest in just 4.1, six-tenths of a second quicker than the old MK3 model's 4.2-litre V8 could manage. As before, this family estate can hit 174mph on the Nurburgring (if you specify the optional 'RS Dynamic' package) but is just as happy collecting your dry cleaning. You only truly get a sense of just how fast it is by following behind in something else. The engine's power flows to the quattro permanent all-wheel drive system via an eight-speed tiptronic auto paddleshift gearbox. In regular driving, the system delivers more power to the rear axle. Its purely mechanical centre differential directs 60 percent of the torque to the rear axle and 40 percent to the front. If undesired slip occurs at one axle, most of the power is automatically and rapidly redirected to the other axle - up to 70 percent to the front or up to 85 percent to the rear axle. The high locking values enable a clearly defined torque distribution and highly precise interaction with the control systems of the ESC and wheel-selective torque control. The driver can tailor their personal driving experience via the standard Audi drive select dynamic handling system. There are five profiles available: comfort, auto, dynamic and the customisable, RS-specific RS1 and RS2 modes. The standard-fit RS sport suspension sets the Audi RS 4 Avant another seven millimetres lower than the standard S4 with sport suspension. An 'RS sport suspension plus' package with 'DRC' 'Dynamic Ride Control' is available as another option, as are ceramic brakes and RS-specific dynamic steering.
Audi RS 4 models have always blended just the right amount of discretion and malevolence. They've never been head turners but let your eye linger long enough over one and there are enough clues that this isn't your garden variety load lugger, something that continues with the improved version of this fourth generation model. The front section has been completely redesigned. The Singleframe is wider and flatter than its counterpart in the A4 model line, and in common with the RS 6 Avant and RS 7 Sportback the grille features the three-dimensional honeycomb structure in gloss black that characterises the RS model series. To give it a clean look, the Singleframe is frameless - the new 'eggcrate' grille with the RS 4 emblem is inserted directly into the bumper with the large lateral air inlets and vertical flaps. The shape of the standard Matrix LED headlights with their darkened bezels has also been redesigned. The wheel arches with their quattro blisters are each 30 millimetres wider than the A4 at the front and rear. Gloss black design elements positioned right next to the headlights also help to emphasise the width. Inside, the main change is a new 10.1-inch MMI touch centre-dash display which provides acoustic feedback and takes over the functions of the previous rotary pushbutton on the centre console. The driver can use the RS monitor to call up an overview of drive system component temperatures, maximum g-forces and information regarding tyre pressures and temperatures. As before, there's an Audi virtual cockpit digital instrument display where special RS displays provide information on tyre pressure, torque, power output, engine oil temperature, lap timings, acceleration measurements and g-forces. The shift light display prompts the driver to upshift when the rev limit is reached.
It's vaguely pointless to try to assess the value proposition of the RS 4 because it effectively competes in a class of one. Yes, you can buy rapid estate cars from other manufacturers but the RS 4 has a very specific appeal, four wheel drive and commands a loyal customer base. Needless to say, Audi will have a queue for every car it imports, even at an asking price of around £65,000 - or more if you want the lavishly equipped 'Vorsprung'-spec model. The RS 4 Avant is factory-equipped with 19-inch forged aluminium wheels with 265/35 tyres. Various 20-inch designs are available upon request, including a new fully milled five-arm wheel painted completely in matt bronze and running with 275/30 tyres. Powerful RS steel brakes with perforated composite discs ensure confident deceleration behaviour. They have a diameter of 375 millimetres at the front and 330 millimetres at the rear. The six-piston brake callipers with RS logos are painted in black, or optionally in red. As you've probably figured out, it's possible to go quite large with options on this car. At least you shouldn't have to pay out for additional safety features. More than 30 driver assist systems underline the all-round characteristics of the high-performance Avant. Many of the options are bundled in the "tour" and "city" packages. They include the adaptive cruise assist with stop & go function for automatic distance control, the intersection assist, the lane change warning and the kerb warning.
The high-output V6 impresses not only with its strong performance but also with its high level of efficiency. In the WLTP driving cycle, it returns up to 30.7mpg, which corresponds to 211 grams of CO2 per kilometre. This constitutes a consumption reduction of 17 percent versus the previous model. A decisive factor in this is the new TFSI combustion process, which is known as the B-cycle. It has been specifically designed for the partial-load range, which is the predominant operating mode during normal use. In the case of higher loads and rotational speeds, the two-stage Audi valvelift system (AVS) closes the intake valves later, thereby increasing the opening duration to a crank angle of 200 degrees. Simultaneously, valve lift increases from 6.0 to 10 millimetres. The cylinder charge thereby increases accordingly, as does response. At point of purchase, be wary of loading the car full of options. Big petrol engines aren't great for resale in this country anyway, so don't make things worse by ticking loads of boxes on the spec sheet. While it might seem worthwhile at the time, it's unlikely the next buyer will pay extra for a lot of the equipment. The warranty is for three years or 60,000 miles. However, this can be extended for a fee.
The Audi RS 4 Avant has managed to carve out a specific and profitable niche in the performance car market and with good reason. If you have the funds not to have to worry unduly about trifling matters like fuel bills, then it's the consummate all-rounder. It's crushingly fast, effortlessly discreet, beautifully finished and genuinely practical. It'll do anything that a regular A4 Avant will and a whole lot more besides. It's as quick as a Porsche 911 yet it's good for both the school run and a kerb-hopping lap of the Nurburgring. Drive it and you'll experience a slightly guilty thrill as if something this much fun really couldn't be legal. One day cars like this might well be legislated out of existence. In the meantime, enjoy this one while you can.