German tuner ATT-TEC has come up with a superb power package for the BMW M3 Convertible – which presumably also fits to the M3 Coupe – with no less than 520-hp. It transforms the M3 from just a good coupe to a great coupe, with super performance. They’ve also tweaked the looks a bit, but really, it’s the engine that dominates everything in this car.

ATT has fitted the M3 with a set of one-piece forged 8,5×20 inches ADV.1 rims in 5.1 design on the front and 11×20 inches ones on the rear. These classically beautiful wheels cost €7,150 and are wrapped in Vredestein Ultrac Sessanta tires 245/30R20 on the front and 295/20R20 rear.

The wheel/tire combination is complemented by the €1,929 Inox Line III Variant lorry track coilovers. The result in the perfect fitment of the wheels inside the fenders.

As for the engine treatment, ATT has used G-Power Compressor kit by G-Power that costs €11,430, and further tweaked it with a new ECU remap, and a set of 2 x 90 mm diameter stainless steel exhausts. The result is an extra 100-hp to play with.

As a little extra something, ATT has also wrapped the car in a €2,600 matte black film, bringing the total cost of tuning to €26,573.