At the turn of the new millennia, BMW introduced the E46 M3, renowned for its 3.2-liter inline-six that produced 343 horsepower, making it the most powerful naturally-aspirated engine ever built by BMW (the engine it built for the McLaren F1 notwithstanding). In 2007, the E92 M3 arrived sporting a completely new look and a 4.0-liter V8. The tuning world has been delivering aftermarket packages ever since, and when the fifth-gen M3 (F80) arrives in 2014 powered by a 450-hp turbocharged straight-six, expect more of the same. In the meantime here's four of the best we've seen over the past year.

BMW aftermarket specialist Alpha-N Performance took the M3 (E92), optimized the ECU, installed a carbon airbox to improve the V8's cooling and added an Akrapovic titanium exhaust system, raising output by 30 hp to 450. A lightweight aero kit optimizes airflow and keeps weight down. A carbon racing spoiler was fitted up front while at the back there's a carbon rear diffuser and rear wing. Inside, an exclusive set of Recaro Pro Racer HANS seats have been added to increase support. Optional extras include a roll cage and carbon doors, hood and rear lid, and to better handle the car's improved power-to-weight ratio, Alpha-N installed a KW suspension and fitted 19" OZ alloys.

Aresing-based tuner G-Power's BMW M3 Coupe (E92) received the company's Tornado RS conversion, which consists of taking apart the 4.0-liter V8 and rebuilding it with a new crankshaft and Mahle pistons, raising the displacement to 4.6 liters, and adding the company's Sporty Drive SK III supercharger system, a carbon-fiber air box and titanium exhaust with carbon tips. The result is an output of 720 hp for a 0-62 time of 3.7 seconds and a 205mph top speed. An adjustable Clubsport coilover suspension kit and G-Power's 20-inch alloys were added, and the project was completed with some aero elements, namely a lower front spoiler, and replacement hood and boot lid made from carbon fiber.

Vorsteiner created a widebody kit for the E92 marrying functionality with performance. It includes redesigned front and rear bumpers, with the front getting additional vertical vents for improved airflow. At the rear, an integrated diffuser features longer aero fins to help create additional downforce, while flanking the rear bumper are vertical vents with carbon-fiber inserts. The GTRS5 was limited to 40 models worldwide, and the complete list of components include carbon-fiber bumper integrated with a chin spoiler, carbon-fiber wide-arch front fenders and rear quarter panels, extended side skirts, a chrome trunk badge emblem, and Vorsteiner VS-310 3-piece concave forged alloys.

Miami-based luxury car tuner Velos Designwerks created a kit whose most eye-catching exterior modification is the addition of the company's own custom lightweight forged alloys, finished in a special shade of dark bronze. When combined with the red brake calipers, steel discs and Alipne White body paint, the overall ensemble is one to behold. Brembo supplied the brakes, while Velos turned to KW for its V3 lowering suspension module. These modifications were necessary as the M3's 4.0-liter V8 was fitted with an ESS VT625 supercharger kit that, courtesy of 8 psi of boost, gives the high-performance coupe an additional 200 horsepower for a total output of 625 hp.