Originally Posted By: L_Sludger
They don't make the 335i anymore, do they?
No. The N55 six has been replaced with the B58. Likewise, the N20 four has been replaced by the B46. The B series motors are modular in the sense that the engines all have identical cylinder spacing as well well as bore and stroke(500cc per cylinder). This allows three, four, and six cylinder engines-gas or diesel-to be built on the same assembly line.