Which phono preamps modify to top notch?

Lamm LP2 - change tubes, caps, RCA jacks and the input Xfrs. 6 hours work, approx. $1k to 1k5 parts.
Easy to perform except for some nasty work changing the poor RCA jacks for pure silver ones.
Not balanced output however except you are willing to do more work.
Afterwards its one of the top 5 phono preamps on this planet - regardless the price tag.
Others will have other favorites, but this can be bought real cheap on the used market and provides an excellent basis which is easily upgradeable.

Ayre P-5xe phono stage. Only so so as stock. When my friend got done modifying it the sound was completely transformed. Huge soundstage with incredible micro and macro dynamics.

I find the current used price/performance ratio of the Aesthetix Rhea outstanding. Great air, well balanced sound, excellent low level detail and sound staging, blah, blah, blah with the audio jargon... it makes really believable music . There is the option available to upgrade to a Signature version as well. This unit to my humble ears was worth every penny at its retail pricing and to see them for less than half of that, I find just plain crazy. And yes it is dual mono, fully balanced architecture beyond the phono input.

Happy (analogue) Listening!

Rhea Input Stage is single ended, so no fully balanced arcitecture,

Reinhard