+1, especially the separate lines. I prefer AirLift bags over air shock solutions plus they are easier to install and you have more flexibility in rear shock choices.Airlift bags plumbed seperate are going to be a MUCH better option for stopping the rear from sagging.
"The springs for these cars are of 2 basic rates--expressed in "newtons per Meter", a metric conversion of "pounds per inch" of spring compression.
SS & 9C1 sedan, wagon front - suspension RPO 7B3, FE3, FE4 & others
front - 77 n/M (other sources indicate a 440# "rate" for this spring family) - 45% rate increase over 53 n/M springs (below)
The range of 77 n/M springs (same basic wire size, OD, etc) is formed/cut to lengths resulting in various ride heights, SS-specific spring providing the lowest ride/trim height measurements
rear - 27 n/M (SS-spec spring is 154# "rate") - 50% rate increase over 18 n/M springs (below)
other sedans (those not using FE3, FE4, or 7B3 suspension packages--and possibly FE2 & F41)
front - 53 n/M
rear - 18 n/M
rear - 37 n/M
Compared to the 77 n/M front springs (assume 440# rate), the 7268 (750# springs) are 70% higher rate--significantly more energy to deal with.