Two advanced biturbo Direct Injection engines can fine-tune their fuel and spark within a millisecond. The E400 features a 329-hp 3.0L V6. A 402-hp 4.7L V8 powers the E550. Quick and lean, they create a torrent of torque with only a trickle of emissions. ECO Start/Stop saves even more fuel with automatic engine shutoff at stoplights.