Yes, it is an upgrade.KEF Ref 1 has more defined treble, mids are more detailed and tones are more accurate, bass goes deeper and has more substantial weight.
That said, it is not necessarily better, as the special 40 is less neutral, produces louder bass and slighlty more elevated 100hz which makes it more "satisfying" to some people. A friend of mine did that exact same upgrade although he has a H190 instead. He finds the Ref 1 to be the superior speaker, but still misses the more "fun" (I can't believe I'm saying this for dynes) special 40.
That said, it is not necessarily better, as the special 40 is less neutral, produces louder bass and slighlty more elevated 100hz which makes it more "satisfying" to some people. A friend of mine did that exact same upgrade although he has a H190 instead. He finds the Ref 1 to be the superior speaker, but still misses the more "fun" (I can't believe I'm saying this for dynes) special 40.