iL6 engine is silky smooth like strawberry whip cream.
4 cyc once u stand outside the car with the engine on, u will hear the car rattle like taxi.... "tiak tiak tiak".
A year ago, I had a choice to choose between the last batch of 523i and new batch of 520i. It was a no brainier for me then because I cannot tahan the tiak tiak when SE stop the 520i in front of me for test drive. My exact question to him, "Why this Beemer sounds like a taxi? He said all BMW 4 cyc sounds like this. When I accelerated hard from almost stand still, I could hear engine roar like lawn mower but car didn't pull much.
528i acceleration and pull was much better but 23k dearer... in the end I opt for the 523i. Still love the creamy engine and the sound track it generates. However, u no such option in getting a new 523i from PML. U really need to test drive both... then the choice would be much easier for u.
Good luck bro.