The E24 stayed in production for 13 years and is probably the most desirable classic BMW you can use today as a daily driver. But back in 1976, it was also the first BMW of the electronic age. If you don't believe me, just press TEST.
Knowing what an advanced BMW looks like in 2014, it's hard to get excited about the first 6 Series having aerodynamically optimized side mirrors, a bit of plastic sealing around the kidney grille as corrosion protection or water drainage channels. Yet there was something on the left side of the dash that they could call cutting-edge: BMW's first "check control".
It might have only been a system that checks your fluid levels, but that's pretty much the birth of the on-board diagnostics you find in all modern cars. Just don't think about what happened to that inline-six when this early system malfunctioned.