The amp/speaker match is very important to achieve good sound. No doubt your current Klipsch/Primaluna combination is an excellent match. Since you have been accustomed to the dynamics of that combination, changing to a speaker with a much lower sensitivity will likely be a disappointment.
I'm sure the Elac mentioned is a fine speaker, however not a good match for the Primaluna. It's rated sensitivity is 85db, but being a 4 ohm speaker, that must be reduced by 3db for comparison to an 8 ohm speaker. So, 82db with the Klipsch being 101db, a 19db difference. Using the Primaluna with the Elac would be like driving the Klipsch with a 1/2 wpc amp. Also, think about life of the power tubes.
I'm sure the Elac mentioned is a fine speaker, however not a good match for the Primaluna. It's rated sensitivity is 85db, but being a 4 ohm speaker, that must be reduced by 3db for comparison to an 8 ohm speaker. So, 82db with the Klipsch being 101db, a 19db difference. Using the Primaluna with the Elac would be like driving the Klipsch with a 1/2 wpc amp. Also, think about life of the power tubes.