The current BMW M3 is a variation of BMW's 3-series coupe that adds power and performance to the chassis to create one of the most acclaimed sports cars in the world. Making a current (since 2008) BMW 3-series into an M3 would involve costly and difficult tuning and aftermarket additions to the engine and suspension. Making a BMW 3-series look like an M3 is a far easier task. Since the M3 and the standard 3-series coupe share much framework, making the coupe look like an M3 will only require external additions that could cost much less than the difference in price between the two models.
Remove the panels for the front bumper, the side front quarter panels and the rear bumper. Replace the rear bumper with an aftermarket bumper that allows two cutouts for the dual exhaust that matches the M3 style.
Replace the front bumper with an aftermarket body kit that includes front brake spoilers. On the M3, the front spoilers act to cool the front brakes. The aftermarket bumper need not provide a similar function as long as the two openings at the lower front corners are present to mirror the look of the M3.
Replace the two front side panels with 3-series panels with side grilles. The chrome grilles provide ventilation for the E92 M3's 4.0 litre V-8 engine. On the 3-series it will provide one of the distinctive exterior features that differentiate the M3 from a standard BMW 3-series coupe.
Add side skirts below the side panels of the 3-series to give the appearance of a lower stance for the 3-series.
Replace the wheels with compatible 19-inch chrome wheels. The E46 BMW M3 came with either 18 or 19-inch wheels while the E92 has standard 19-inch chrome wheels.
Replace the bonnet with an M3 bonnet with a "power dome." The M3 engine required a raised section of the bonnet for clearance, which is commonly called a power dome. From a distance, when the wheels are indistinguishable and the side grilles are invisible, the power dome stands out as a signature feature of E46 and E92 M3s.
Add a lip spoiler to the rear boot lid. The M3 has a subtle spoiler on the rear edge of the boot. You can have the lid spoiler attached by adhesives for a long-lasting fit.