[Migelito]

Was choosing between two 535xi CPOs and discovered upon the test drive that one of them had quite annoying sound between 1700-2300 rpm, especially on the uphills, so just like the other people describe here - low frequency pressing noise, qualifying as drone, which goes away if use sport mode. I was choosing between nearly two identical stocks and was trying to make my mind about which i want to buy. I draw attention of the sales and they asked techs "wth with this noise". the other car was dead quiet.

this is when it was "discovered" one car of the two had MPE (I said discovered - the both cars just came back from the lease and haven't been even looked at to be certified as CPOs). Techs said the noise came from the disconnected muffler, likely done by the previous owner to increased the loudness. They "supposedly" reconnected the muffler. I couldn't say with 100% certainty i heard the difference, but maybe because test drives were done 3 days apart.

long story short: the low frequency drone on a highway at 65-75 mph is quite annoying, so i keep the car in Dsport pretty much all the time. It is not a big deal in street driving as i love sport mode; on the highway though i am getting probably some -3 mpg... to bad the drone is getting away above 2700 rpm, which is too high for 8th gear and stupid US speed limits, especially on East coast...

still considering to bring it over to the dealership to check the "connection of the muffler" as the car is CPO'ed still...

donno the part number but my tips are black, so i guess.. newer part number.