ESS is developing a supercharger for the N51/N52. I don't own the engine so I don't know its inner workings... but it sounded like the development costs would be high for the number of kits sold, so that's why no one has undertaken the project. And by "development costs" I mean that no one knows how much boost it can hold (cast crank, weird block material) and the Valvetronic engines don't have an easy tap for vacuum (and therefore the bypass valve). I hope they follow through, because I wouldn't mind picking up a 325 rwhp non-M
