This is a feedback forum. I'm not asking anyone to buy into my opinion. All your facts/theories sound great (and I know you're not being argumentative) but the feeling in the seat of the pants while riding on these NEW Metzeler 880's is smoother, quiter, "grippier" than any NEW Dunlop D402 I've ridden on. I am not the type to make statement based on the fact that I spent the money so I have to make myself believe I made a good choice. If I don't like something I'm not too proud to say it. That being said, I am glad I switched.
Good answer. I believe that you are feeling something in the transition to these tires. Between 1997 and last spring I've gone from one D402 to another, obviously not feeling any difference other than the expected new-tire response--but I can't say I noticed a difference with the E3 either. I also never sensed any quirkiness with either, except the well-known rain-groove behavior already mentioned in the D402.