Ayre owners and preamp options: seeking advice

I bought a new Ayre VX-5 twenty a while back and have it paired with the Ayre K-5xeMP pre.  Was contemplating updating my pre which is currently fed by a phono pre (Ayre) and a DAC, both balanced inputs.  Has anyone modded a k-5xemp with a few select parts and improved it?  Alternatively, has anyone added a tube pre to their Ayre amp?  Which ones mate well?  Lastly, upgrading to their new KX-5 twenty would be an obvious choice but I'm not yet ready to make that investment.  Thoughts?