It sounds like you want comfort but more fun/stability. Here is the suspension on my DD/road-tripper Fleetwood. Each change had an impact.
Rear swaybar - IIRC, the regular Fleetwood bar is already same as Impala, so no change here.
Front swaybar - I noticed a good difference going to the 30mm bar from the 28mm.
Control arm bushings, front/rear - big improvement in comfort/handling.
Trailer hitch - less rear end shaking over bumps/potholes.
Dick Miller braces for the rear control arm body mounts - more stable in changing camber and over bumps.
Bolt-in front brace at swaybar mounts - crisper turns, less shaking on rough pavement.
Bilstein shocks - huge improvement front and rear - turning, bumps, potholes, dips, braking. Factory air shocks are not good for body lift/roll in turns.
Aftermarket rear lower control arms with poly (UMI, Metco, etc.) - less jiggling over washboards, more stable in turns. Rear UCAs are stock and new rubber.
Springs - front are still FE1, should be a little stiffer. Rear Moog cargo coils are too stiff--car is much flatter in turns, but oversteered until I put in the 30mm swaybar. Shoulda changed the swaybar first, then played with springs.
Air Lift 1000 air bags in rear - least useful thing I did. Not helpful with the cargo coils, so I keep them at minimum pressure. Maybe they'll be useful with some slightly softer non-progressive rear coils.
Then it was time for a new 2.5 steering box and 18" wheels/tires. I'm sure the car needs new body mounts (the originals must be shot by now) but it is a lot more fun to drive than it first was.
Rear swaybar - IIRC, the regular Fleetwood bar is already same as Impala, so no change here.
Front swaybar - I noticed a good difference going to the 30mm bar from the 28mm.
Control arm bushings, front/rear - big improvement in comfort/handling.
Trailer hitch - less rear end shaking over bumps/potholes.
Dick Miller braces for the rear control arm body mounts - more stable in changing camber and over bumps.
Bolt-in front brace at swaybar mounts - crisper turns, less shaking on rough pavement.
Bilstein shocks - huge improvement front and rear - turning, bumps, potholes, dips, braking. Factory air shocks are not good for body lift/roll in turns.
Aftermarket rear lower control arms with poly (UMI, Metco, etc.) - less jiggling over washboards, more stable in turns. Rear UCAs are stock and new rubber.
Springs - front are still FE1, should be a little stiffer. Rear Moog cargo coils are too stiff--car is much flatter in turns, but oversteered until I put in the 30mm swaybar. Shoulda changed the swaybar first, then played with springs.
Air Lift 1000 air bags in rear - least useful thing I did. Not helpful with the cargo coils, so I keep them at minimum pressure. Maybe they'll be useful with some slightly softer non-progressive rear coils.
Then it was time for a new 2.5 steering box and 18" wheels/tires. I'm sure the car needs new body mounts (the originals must be shot by now) but it is a lot more fun to drive than it first was.