Upgrading Preamp, need help, Ayre K-5xeMP or Jeff Rowland Capri S2 or VTL TL-5.5 v2?

Dear audiophiles,
Please share if you had strong experience with one of the preamps listing below.
1/ Ayre K-5xeMP to match with my Ayre cd player
2/ VTL TL-5.5 v2 to match with my VTL amp
3/ JR Capri S2 version to improve from what I'm already having, the original version.

So, I'm looking for sweet and neutral with a tad of warmth, more refine and high(er) end sounding. Basically, a better preamp that will better match with my current:
. CD player, Ayre Cx-7 original version
. Preamp, Jeff Rowland Capri original version
. Amp, VTL ST-150
(Sonus Faber Cremona speakers)

Thank you