Buying and installing new springs from Eaton or ESPO is going to be the easiest way of getting your rear susp done, most members opt for 1" over stock - the extra 1" on the cars that get posted have appealling stance.

I would think with the relatively low miles the originals would be great candidates to be simply prepped / re-arched if necc / reassembled - adding more value to a conv like yours is. If they are S15/hemi spings then do restore them, these are not so easy to find. My guess is the conv springs are even harder to source, so again consider to restore the originals, store them along side any other orig parts you may have if decide on non-OEM replacements.
Either way you go is acceptable ever since Eaton and ESPO making the best springs for Mopar.