Replacement for Audio Research LS-8

Would like to replace my older AR LS-8 pre-amp with another tube pre-amp. Suggestions? would like to keep it under 3K (new or used)

My system:
Rotel RCD991 (transport only coax into)
PS Audio DAC DIII (with Cullen Mod III upgrade)into
AR LS-8 Tube pre-amp (via Kimber SS)into
Channel Audio d200 mono block (class D) via SoundString Cable
Acoustic Zen Adaigo speakers (via anti-cable)
Signal Cable Power Cords on everything

Thanks Much in Advance
How come no opinions here? how bout 4k?
Why do you want to replace the LS8? I'm not sure that it is the weak link in your system.
Just thought there was better over the years? what would you upgrade first? thanks much
I am not familiar with the speakers, but certainly the Rotel piece or the Class D amps. I also can't comment on the PS Audio modified DAC.