Buying Suggestion

Dear community,

I own an AMC CD9 and an AMC CVT3030 amp. Both have been modified and sound waaay much better than the original.
As speakers I have KEF Q70, which I believe are right now the weak part of the system and for which I am looking for an appropriate upgrade.

In principle I would like to hear a punchier, clearer bass and a more spatial sound in general.

According to my previous dealer (in Vienna, Austria - now I live in CA) for the AMC amp with ca. 2 x 30 Watt power the speakers should have between 89 and 92db sensitivity while the low frequencies impedance should not be lower than 4Ohm.

With this said, I am now looking for second hand speakers and a budget which should not exceed $2k.

What would you suggest?

Thanks a lot!

Fabrizio