Underground Racing may have been severely upstaged by AMS Performance at the recent TX2K event, but it still attracts a lot of clients for its twin-turbo conversions. The tuning company specializes in making Lamborghinis and Audi R8s insanely fast and has been fitting turbos to these exotics for a long time now. Back in 2012, we covered a 1,200-horsepower conversion that the company carried out on a Lamborghini Aventador, but now the tuner has stepped up to a new level, becoming the first to strap a pair of turbochargers to the $500,000 Lamborghini Aventador SVJ.

With just 900 units ever being made, this is a remarkable achievement, as is the power that the team extracted from the car.

As you can see from the above video, this thing doesn't hang around and sounds absolutely tremendous, thanks in part to titanium induction and exhaust tubing. We'll get to the power figures shortly, but first, some component specs. This car is fitted with a JRR MoTeC M1 ECU featuring Underground Racing's proprietary Aventador firmware to handle all the tuning requirements. Under the hexagonal hood sits a fully built engine with billet connecting rods and custom forged pistons.

The gearbox has also been strengthened with a full billet 1st-7th gear setup with billet drop gears and billet input and output shafts. The front and rear helix differentials are also now billet items to handle the extra strain, as are the custom intake and lower runners.

So what kind of "extra strain" are we talking about?

Thanks to the addition of mirror billet turbochargers from Precision Turbo & Engine, the Aventador SVJ no longer produces "just" 759 hp and 537 lb-ft of torque. Instead, it now generates a whopping 1,600 hp at the wheels (no torque figure is provided). That's just scratching the surface of what this car is capable of, as UR says that if the owner (Chris Tawil) upgrades from the current custom clutch and billet flywheel fitted to the build and opts for UR's race-spec clutch, it will safely generate over 2,000 wheel-horsepower. And the best part? The Aerodinamica Lamborghini Attiva active aero system is still fully functional. AMS may hold the records, but UR is still the king of Lamborghini world-firsts.