upgrading from Spica TC60's to ??

I have owned two pairs of TC50's, and modified the last pair like this: new better binding posts, cardas wiring, remove felt from front. I don't know about the TC60's but I've heard that the TC50's are actually better. Biggest drawback I think is the inablility to bi-wire the TC50's. My other system I use JPW 510's from England; these I think are better (tonal voicing, imaging, dynamics, bass) than the TC50's and are very inexpensive! I highly recommend the JPW 510s. Better than those are the Chario Academy 1's: these are really the best small speakers I've heard with the exception of the Ensemble Reference monitors ($4K)

I also went from TC-50's to TC-60's using a CJ mf2200 amp and MIT T2 biwires. My next upgrade was a pair of Martin Login Aerius (used). Fantastic upgrade, especially after I replaced the T2 with Kimber TC8. Good luck.

Alon I or II. Tracer

I still have a pair of my beloved TC50s. Great speakers but can definitely be improved upon. Try to get a pair of Kinergetics subwoofers (I had the BSC200) which will do wonders for the low end. The Edison Price binding posts are also a major improvement. I eventually upgraded to the Alon IIs but they cost 4 times as much as the TC60s.

It might be better to hold off selling your Spica until you've found a worth replacement.  I know it complicates the funding, but is a more conservative approach that won't leaving wishing you'd done something differently.  Good luck.