Helped a guy change the oil in his BMW 325ci today. Not sure why they are called E46 but it's a nice size I6. Maybe it's the E series, 4 door 6 cylinder model. It has an oil filter housing on top and the after market fliter was a little crushed, not sure why. I installed an OEM fliter.

 

BMW generations are informally referred to by their chassis numbers, "e46" in this case. They were intended for internal use only by BMW and the numbers don't mean anything (not that I've ever found out, anyway). The previous 3-series is labeled as e36, and the one before that, e30.