I put some of John's springs in my 1800 to lower it (had to roll the front fender lips -- I wanted it down there, so did not use the spacers), and the ride is at least as good as with the originals on decent pavement.

Some months later, I put in poly bushings, even though the OE ones were in good shape, and the ride got subjectively *smoother* -- it's just that much tigher and more controlled, with no increase in harshness whatsoever. Also, that feeling of the rear Bilsteins being a bit stiff (many 1800 owners complain of this) disappeared entirely.

No problem with the big rear bushings not having enough compliance, FWIW...