It sounds pretty good too.
The F80 BMW M3 and F82 BMW M4 have been replaced this year, with their buck-toothed successors kicking up a storm on the internet for their styling. But people seem to forget that when the F8X generation arrived, it too was berated. Many disliked the styling, and still more took issue with the sound of the cars. See, a front-engine, twin-turbo setup typically requires unequal lengths of downpipes to the exhaust to get around all the other auxiliaries in the engine bay and below, which tends to result in an unpleasant, metallic sound. To get around this, aftermarket tuners typically build equal-length exhaust setups, but another company has found a better, more efficient way of improving the sound of the twin-turbo S55 engine.
The trouble with an equal-length exhaust is that the added complexity typically adds weight, but AWE Tuning says that its newly designed muffler negates the need for such a system. This muffler forms part of the first of two systems offered for the cars, namely the SwitchPath system. This valved exhaust can provide subtle, socially acceptable noises using the car's existing adaptive exhaust profiles. But when you switch the car to Sport or Sport+, the valves open for much more noise. Despite the open valves, the tuner claims that the X-pipe design makes the S55's infamous rasp a thing of the past. This three-inch system also boosts performance by 12 horsepower and 16 lb-ft of torque.
If you don't care about the sensibilities of a harmonious society and just want a noisy ride at all times, AWE recommends its Track Edition exhaust. Like the SwitchPath system, this is made from T304L stainless steel, just without the rear muffler. As a result, you save 22.5 pounds of weight. To avoid any issues when you switch to sportier drive modes, the exhaust comes with valve simulators so that the factory exhaust valve motors don't throw an engine light. Both systems are 50-state legal and can be had with a choice of either chrome silver or diamond black exhaust tips measuring 102 millimeters in diameter with double-walled slash-cut tips. As for pricing, you'll have to find your nearest dealer to get a quote.