Seeking opinions on best amp match for Aerial20T

I've been enjoying (loving) my new speakers now for about a year. Over that time, I've noticed some shortcomings of my system, which I believe are attributable to the amps, and am now seeking to replace my current amps. Here's a short list of my setup;

ML326S
Sony SCD1 (modified)
2xML334s (one per speaker)
Harmonic Tech magic speaker cables
Cardas Golden cross balanced

My main two gripes with my current setup are;

the bass seems a bit soft, not well defined. Volume is good though.
imaging is not quite as good as good as I recall when auditioning the 20Ts

I'm considering either Krell450Mcx's, 2xML336's or ML33H's. Any thoughts?