A suspension lift can be done with taller springs and/or spacers. You would have to remove those and replace them with OEM springs, or H&R 1" lift springs. Along with springs, you'll have longer shocks to match, so you'll need OEM length shocks or a little longer if you keep some lift. You may have aftermarket adjustable track bars, in which case you can adjust them for the new height. Or the PO may have kept the OEM track bars. You'll probably need shorter sway bar links (or adjust them if possible). You might have a track bar relocation bracket on the rear axle which should come off. You might have an SYE and DC driveshaft in the rear, and possibly adjustable control arms.
Sorry, but there is a lot to look at before deciding how to modify it. Pictures of the suspension could help people here see what you've got to work with.
Sorry, but there is a lot to look at before deciding how to modify it. Pictures of the suspension could help people here see what you've got to work with.