Be prepared to spend a sizable sum to get a significant improvement. I just upgraded from the original Freya to an Atma-Sphere MP 3. The Atma is 10 times the price of the Freya and considered to be one of the better preamps available at any cost. Is there an improvement? Sure. But it also shows me how good the Freya really is.
Thanks for the response and insight, good to know. Based on my experience and what everyone else says, I was pretty sure the Freya was a high performer. I am intrigued by the Benchmark LA4, though it may just be a lateral move with a different sound.