Wow (old timer chuckling)
I used to own an E36, and it's a first of sorts for BMW, but it's hardly timeless IMO. It was the first to be designed on CAD, but was built with recycling in mind . . they intentionally weren't made to last that long, and thus were the most problematic cars for BMW. They were manufactured at an era when marketing trends indicated that consumers were buying new cars every few years anyhow. I'm not saying it's a shitty car because I loved mine to death. But timeless to me is the 114 (which includes the 2002), the E21, E24, and even the E30 would be considered more timeless than the E36.
Inspiration? For me, it was watching a black E21 320i cruising along the Mass Pike, windows down, and blasting Steely Dan's "Do It Again". That was almost 30yrs ago, and I still see it clear as day in my mind. Then in the 80's I was absolutely obsessed with the E24 635csi. It wouldn't be until 2005 when my love for BMWs was rekindled, and I got my hands on a '92 325i. Previous to that, I'd owned about 15 cars, and none drove like it did.