We’ve delved into the Performance BMW archive to dig out this throwback feature on a bonkers supercharged BMW E39 M5.

“Don’t judge a book by its cover” is an age-old adage instilled in us during our youth. While it is one of the earliest morals taught, it is too often forgotten as we grow old. Taking past experiences and using them to make prejudices towards a result which we expect to be true can get us into trouble and that is the case with Matt Benson’s E39. What looks to be a civilized saloon is in actuality a complete and utter lunatic. Don’t be fooled – this unapologetic M5 will leave you scratching your head when launching from a red light or as it commands curves, winding through the mountains.

E39 M5

Maintaining a balance of ferocity and modesty is not an easy task and while on paper it might be contradictory, we assure you that Matt’s E39 M5 is a textbook example of a proper business saloon. The key to retaining modesty is doing without the wild colours, aggressive aero, and flashy wheels. Aesthetically, it has to be something to simply get you into work without being the topic of conversation among co-workers gathering around the water cooler. However, that commute to and from the office is a different, exhilarating story. In order to fully appreciate the final product, we need to briefly highlight the evolution of Matt’s mods and previous cars.

E39 M5

Matt Benson has always had an affinity for V8 muscle and taking the more subtle approach is something of second nature for him. His first car was a Ford Mustang 5.0 LX “Fox body” which, in a sense, was a sleeper in its time compared to its sister version, the Mustang GT. He drove that LX into the ground with over 200,000 miles on the odometer. After many advancements up the automobile food chain, Matt traded some American torque for German refinement as he found himself in another V8, but this time in the form of a 2000 E39 540i Saloon. Though Matt was satisfied with the graduation to the European sports saloon and recognized it as a big improvement, the horsepower bug bit him hard. Dinan parts made their way all over the 540i to increase the performance in both the handling and the engine, pushing it to 350hp. Knowing his reasonable limitations had been met with the 540, yet still wanting more out of his car, Matt set his eyes on his current ride – this 2000 Carbon black on Caramel leather M5.

E39 M5

He found this car over a decade ago, desirably, with one previous owner and only 13,000 miles logged. Immediately, the performance difference was prominent between the 540i and the M5; the torque off the line and the way the car hooked in the corners didn’t leave him with seller’s remorse over the 540i. While he was tacking on roughly 50,000 miles of his own back and forth to the office and on spirited drives, Matt was continuously adding mods to enhance the performance even further. As superior as he felt the car was in comparison to his previous cars, it wasn’t quite enough. Relentless and back with a vengeance, the mod bug bit hard this time, and it did not let go.

E39 M5

Matt’s first modification to the M5 didn’t lead to horsepower gains per se. Back in 2005 he sourced a Dinan 3.55 differential and while it is one of the biggest improvements that you can make to a naturally aspirated car, ironically, it has nothing physically to do with the engine. Over the years it served its purpose, but as Matt says “I guess I modded a mod” and changed the rear end out to a 3.62. The tight gear ratio shifts the power band, launching the car and virtually making first gear useless in the best way possible. Surrounding the differential in the rear is a matching Dinan high performance exhaust, which flows out back from a Supersprint four-into-one stepped exhaust manifold system. Above the manifolds, under the bonnet, lies a Dinan cold air intake and Evolve Alpha-N tune with MAF delete and while this combination achieved Matt’s 450 horsepower goal, it was time to raise the bar yet again.

E39 M5

Chasing greater horsepower and maximising the NA bolt-ons, he crossed the threshold into the forced induction world. Matt commissioned Autocouture Motoring in northern NJ, well-known for its work with BMW and supercharging the E9x platform specifically, to do the work. The team installed an ESS Tuning VT1-560 supercharger system along with an Aquamist meth injection kit. To handle the horsepower increase and fight the ravages of age, Autocouture also installed a Dinan subframe reinforcement kit at the same time as the performance upgrades. The combination of the Dinan differential chewing through first and second gear with the pull of the ESS supercharger and meth higher up the power band is a visceral experience that delivers an exceptional one-two punch. In fact, when Matt was asked what his favourite modification to the car has been, he responded happily, “I have two favourites, the first being the supercharger, which brought the biggest smile to my face, and second would be the shorter diff, it’s like a 50hp equivalent increase!”

With all of this newly-added power he now addressed the other areas of importance: brakes and suspension. Matt went top shelf when choosing suspension, opting for the JRZ coilover kit and set the car up slightly lower than the stock ride height, maximising suspension travel and comfort while optimizing the performance that the JRZs offer. StopTech ST60/ST40 brakes at all four corners enhance the stopping power tremendously, with six-piston calipers up front and four-piston calipers in the rear, both sets finished in silver to keep the M5’s modified appearance at a minimum.

Matt loved the car’s aesthetics, especially its finely crafted, unadulterated exterior however, he needed a wheel that would clear his brakes and be lighter in weight than stock, while still maintaining the M5’s factory appearance. Wanting to mimic the style of the OEM M5 wheel, Matt, along with the crew at ACM, carefully selected the HRE Classic 301 monoblocks. Taking it a step further, he went with HRE’s gorgeous, custom, hand-brushed finish with a dark-tinted clear coat, tying them in with BMW’s factory chrome shadow finish on the M5’s original wheels.

This M5’s interior is straight out of a BMW catalogue with the smooth caramel-coloured hide fl owing from the seats onto the extended leather lower dashboard, with just the right amount of wood trim. Nothing is out of place nor unnecessarily added. Under close examination, only an aluminium pedal set and short shift kit can be spotted in here and even at that point the SSK is still capped off by the stock wood knob to maintain the factory look and feel. Matt was highly selective with every modification made to his M5, and held the highest of standards for how this on-going project was executed.

“While the car is more than 16-years-old, it rivals anything on the road currently,” Matt says and we’d have to agree with him, it is completely relevant in every way to any of the European sports cars of today. The gentleman’s executive saloon is one that does not cry out for attention, but rather discretely delivers to those who know what they’re looking at. Each modification was carefully considered and completed with one goal in mind, which was to make the car perform at its full potential. His car takes everything that was incredible about the E39 M5 and sharpens it to modern standards, making this one of the most fun cars you will ever drive.

Tech spec:

Engine and Transmission

4.9-litre V8 S62B50, Supersprint four-into-one exhaust manifolds, ESS VT1-560 supercharger kit with Vortech V3 supercharger, Howerton Aquamist HFS-3 system, Dinan performance velocity stacks, Dinan high-flow performance exhaust, high capacity electric fan, oil separators. Six-speed manual gearbox, CNS Racing 10.5 Kevlar clutch and dualmass flywheel, Dinan short shifter kit, 3.62 LSD with three clutch ramps and polished ring and pinion gears

Chassis

8.5×19” (front) and 10.5×19” (rear) HRE 301 monoblock wheels with 245/35 (front) and 275/30 (rear) Continental tyres, Dinan subframe reinforcement kit, Dinan front tower strut brace, Dinan camber plates and monoball front ball joint kit, JRZ Stage 3 suspension system from Dinan, Beast Power heavy-duty anti-roll bar brackets, StopTech ST60 BBK with six-piston calipers and 355x32mm discs (front) and ST40 BBK with four-piston calipers and 355x32mm discs (rear)

Exterior

Tinted windows, Depo angel eye upgrade kit, front lower bumper grille with aluminium mesh brake ducts

Interior

Black carbon fibre trim, aluminium pedal set, widescreen nav upgrade

This is a feature taken from Performance BMW Magazine. Words and Photos by Matt Petrie