The new BMW M5 is also closer to the size of a 7 series from 30 years ago. Additionally, even with AWD being added it's 200lbs lighter than the last gen was. Cars are certainly heavier on the whole than they used to be, but lightening them is starting to happen again and they're much safer than any car from decades past.

The e28 M5 is more comparable to a 1 series now.

The e28 has a shorter wheelbase than the 1 series sedan (but is longer overall due to its stylish 80's big overhangs...) It is also narrower than the 1 series.