Preamp upgrade path?

[AGS]

Greetings! I am new to the forum and would like some advice on a possible replacement/upgrade path for my AR Ref 2 preamp. After all these years, and new tubes, the Ref 2 still sounds great to me. That said, I have to believe if I compared the Ref 2 to a more recent model I would pleasantly surprised. Any experiences or comments on upgrading from the Ref 2 to a Ref 3 or a Ref 5SE would be most appreciated. Thanks Al