I think you are looking for the amp with the largest current. That will be AMG STA.
Power = Current x Voltage
An amp could have more power than another but with less current. AMG STA was specifically designed to deliver a very large current (10A is huge) even though ST-10 has slightly more power than AMG STA.
I am interested in ST-10 and STA-9X and am considering to purchase one of them, however I feel hesitatation to choose because although ST-10 cost higher, it was launched few years ago, technology-wise would be not updated as STA-9X ? I like vocals and classical music, and am using a pair of JMR speakers (91dB sensitivity).
Somebody told me that using amplifier of higher power output, it would over-damp the speakers, is it true for mine ?
Please let me know more about Nuprime amplifiers for choosing the right one.