Paradigm Studio 80 ver1, Upgrade to what next?

Looking for respectable suggestions as to what to upgrade to from my 1996 Paradigm Studio Reference 80 ver. 1 speakers. (I have already had to superglue the dustcaps on the 8" midranges and bass drivers as they have came partially off due to age). I am looking for a speaker that will show a outright dynamic difference with smoother midrange and midbass (and the speakers would be bi-wired). I am looking for a speaker with better transparency and resolution. I use only a 2 channel system and need the next speaker to produce the same or better sounding low end the 80's do. I would be looking to just drop in replace the speakers and not upgrade any other part of the system at this time due to budget constraints. I would be looking on the used market ONLY and the most I would spend after I sold my 80's to upgrade is between $1500-2000 (is this even a possible price range or does paradigm 80 ver1 a better value than most higher costing speakers?). Thank you for looking. I am up to any suggestions and that being upgrading to any other paradigm speakers (ie: 100's ver2) or such. Thanks