During my college years at Florida (go Gators) we lived in Miami and my father owned a light blue Imperial four door hardtop. My recollections of this car are of a very poor quality product, some items from memory:
1) Door handle mechanism fell apart, we had to take the doors apart and reassemble (I also remember we did some redesign as the pull handle mechanism was poorly designed).
2) The seats were very thin, not much padding, and wore out prematurely.
3) The side windows were curved and never lined up properly front to back (hand one on power window switch, hand two guiding the window).
4) The air conditioning condenser, I believe, was right in front of the radiator and over heating was a regular occurrence in South Florida's 90 degree summers.
I also remember going back to the dealer, with my father for service and seeing a very irate customer complaining about the poor quality of his Imperial and him saying that he would never buy another one.
These memories have stuck with me over the years and I often wondered if the 1957 (and probably 58 & 59) quality was the downfall of Imperial as they never again came close to the 1957 sales volume. I would be very interested in other members comments on this. What has been the experience of current owners of 1957 - 59 Imperials?