Simple--literally. No real obnoxious drivers' aides (impairments, really), a near perfect weight balance, and a smooth, high-revving normally aspirated six cylinder. Oh, and you don't really have to monkey with the suspension bits to get it handle well either--it already handles quite well. In fact, according to Motor Trend, the E36 M3 posted better slalom times than a contemporary Corvette, and was on par with a Porsche 964 (ironic since I just posted one yesterday.)
Also, with a weight of under 3200 pounds, the E36 is nearly 500 pounds (or more) lighter than the current car, and performance of the E36 is only marginally slower, and probably not noticable in the real world. Progress? I beg to differ. While the E92 is certainly a "super car", the price is ridiculous. The E36 M3, from what I remember, did not cost Porsche 911 money, not did it require precision servicing to keep it running right. One more thing. The old car has quite a bit of an aftermarket in terms of body styling, wheels, and actual performance tuning bits--and the best parts? These bits don't require and arm and a leg to purchase. Again, progress? Definitely not.
I could go on and on about why the E36 is superior to the E92, but I'll save that for another day.
I often see BMW's iconic M3 in various modified forms; stock, or close to it, is a different story entirely. Throughout my years if carspotting, for every stock M3 there are maybe four or five (distastefully) modified one, so this example presents a nice surprise. The paint is stock, and being black, it avoids the flashiness that's often attributed to the majority of BMW's M-product stable. The wheels are a factory option, and these look better than the other factory wheels which have a slightly more intricate patten, (and look quite terrible in comparison).
Inside, this example appears stock, and the leather surprisingly is not worn, considering this a supposed to be a drivers' car. Funny that, because nearly all of the stock ones I see are pampered and treated almost like show cars rather than cars that are flogged with the anger of Adam Sandler in a 1990s movie.
While I do like the 3 series of today, I much before the ones of days gone by, and the E36 is currently a favorite--and will likely be so for the forseeable future.