BMW still offers them in the six-banger models. There is *something* about an inline six.
They are inherently smooth...............
I had a great BMW with a straight 6 when I was stationed in Germany. Bought it used for $3,000 in 1994, drove it 3 years all over Europe, and sold it for $2,500 in 1997 to another soldier when I PCS’ed. One of the best purchases I ever made. It was a sweet ride on the autobahn up to 130 mph before I chickened out!