Thanks for all the comments. It was a great trip, and I'm glad you enjoyed the read.
I didn't fully break in the M3 yet, so I can't do a full performance comparison except for my experiences in other E92 M3s. I can say that every generation of ///M I have driven has to be manged differently.
Note: These are only my personal opinions. I am not a professional driver or journalist, so others may have different experiences.
E30 M3 - A hoot around town and at low speeds. Must manage momentum (try to never brake). Great visibility, and a basic cockpit (no stability control, direct feedback). Buzzy engine at highway speeds, and is now slower than modern hot hatches.
E36 M3 - Still very light, more power, better at highways, great for track use (17 inch wheels and low curb weight
) Less rearward visibility compared to the E30. Still gets pretty good gas mileage! As a daily, I miss some of the safety features and stereo controls on the steering wheel and unlocking the doors without the key.
E39 M5 - Monster motor, great handling, and torque so that you don't have to always shift or rev out each gear. The last of the great old school M5's. E60 is too tech laden, and the new M5 is the size of a 7 series, so I think it's getting a little too big. Started my love affair with ///M motors, and a major factor in wanting an E92 with the V8 engine. Great car on the street or occasional HSDE, but not good for low speed autocross where it can't hide it's weight.
E60M5/E63 M6 (From ///M School only) - SMG was not smooth enough and needed more development. M5 was much more of a drivers car than the M6. M6 confused me as it didn't drive nearly as well as the M5, so as a pure autobahn blaster, I think all you would need is a 650i. Coming from 400hp in the E39, I could not see being able to use 500 hp. E60 M5 redefined quick! Terrible gas mileage.
E86 M Coupe - Old school sports car. Sitting over the rear axle you feel exactly what the rear tires are doing. Short wheel base means it will snap on you quickly. Required lots of practice on the wet skid pad to get the feel of the rear end to be able to mange it. S54 motor needs to be reved to be enjoyed (this was the biggest shift I had from driving the E39). The steering rack in that car was my favorite from a driving perspective as you really never needed to move your hands from 10 and 2 even on a tight autocross course. Visibility was terrible out the sides or rear, and the car truly felt like it was shrink wrapped around you. The seats hugged you, you could sit low so you felt in the car, not on the car. Small car was difficult for a week long road trip to Alabama for Ofest. Such a classic exterior, similar to old school Ferrari's. The glove box is a joke. I'm not should you could even fit a pair of driving gloves it in. I do miss that car.
E92 M3 - Puts me back in a 400 Hp V8 ///M car!!! DCT is a massive step forward from the SMG on track and on the streets. So far has a heavy steering feel, with feedback somewhere less than the M Coupe. More room, so I can bring some friends or pack more stuff for Ofest '13 at Leguna Seca
Hoping the different shift, suspension, steering settings will allow for the duel personality of daily use and weekend hooligan. Amazing grip but less feedback than the M Coupe. Good visibility out the back. Better all round car for me, but I don't think it will be as fun at autocross events as the M Coupe, so the E36 may take on some of those duties. The car makes 80 mph feel like 60. It just feel planted (helped by higher weight) at speed. Also from a long trip comfort level I felt better getting out the M3 after 7 hours of driving than I did in the M Coupe.
New M5/M6 - ??? haven't' driven.