Had my first problem with the 335i at 67k. I enjoyed 7k trouble free miles (got it last November). The charge pipe is known to be weak because the OEM BMW part is plastic. I was doing an aggressive second gear pull when it cracked and disconnected from the clamp at the throttle body. Ordered an ER charge pipe and installed it myself in about 45 minutes.
Total cost: $269 and an hour of my Saturday evening. Man I really missed driving this thing!