Historically, GM's RPO codes tell the tale of what a car has built into it in the various areas, and in this case, any code starting with the letter F has to do with suspension. Years ago, F41 was THE factory's "hot setup", but that has been refined over the years--and one unique exception of the letter designation did exist for police cars.
During the time the 91-96 B-body was built, there eventually were a total of 7 different suspension codes employed, depending on how the order form was marked and when the car was built. These are the codes:
FE1 Suspension, Soft Ride
FE2 Suspension, Ride & Handling
FE3 Suspension, Sport
FE4 Suspension, Special Ride & Handling
F40 Suspension, Front & Rear HD
F41 Suspension, Firn Ride, Handling
7B3 Suspension System, Special Handling
Not all of these options were available in every year from 91-96. For example, FE4 is unique to the Impala SS (and I assume Caprice SS). 7B3 is the 9C1 police package's unique set of components. Some of the codes might be wagon only as opposed to sedan only, but I'm not sure which is which at this point. I'd have to spend quite a bit of time poring over the production parts list to figure out what worked with what.
Still, here are some (most?) of the variables that will be part of the difference in each suspension variant:
--sedan or wagon
--spring rate & height
--shock absorber type/calibration
--control arm bushing durometer
--sway bar size(s)
--presence/lack of rear sway bar
--front sway bar end link material
--designated wheel & tire
--frame material thickness
There are other related items that are unique to a particular suspension code--for example, FE4 and 7B3 cars also had 4-wheel disc brakes exclusively--and things like axle size (7.625 or 8.5) & ratio varied by year and other selected equipment. Most of these variables will not appear on the SPIL (Service Parts Identification Label) on the trunk lid, but have to be searched out in the parts book--of those I've listed above, the spring ID and wheel/tire info does appear on the SPIL.
The other lone item that will be on the SPIL in this category is 8X3 for the SEO
Bilstein shocks--all other shocks are shown only in the suspension option "F" code, even though they have code labels on them (for example on the DeCarbon shocks used on the Impala) that don't translate to the SPIL code list itself.
The standard mods most of us are doing on an Impala or 9C1 will work on any other B-body, no matter the suspension F-code built into the car in production. Some mods may not work as well as others, but the parts bin design gives you the opportunity to pick and choose those you desire or need to restore original performance or to improve it.