Upgrade from Threshold T3?

When I moved up to the Threshold T3 preamp I was gratified by its clarity, openness and imaging compared with the solid state unit I was using before. It was an improvement in every aspect, yet it didn't introduce any of the solid state nasties. It could be that I wont be able to improve much on it if I were to upgrade, but if there's something out there that's clearly better at no more than $3000 new or used I would want to look into it. I lean toward solid state but would consider anything, really. Thanks for your input.