Integrated amp upgrade


I'm using a Classé Audio CAP-151 to drive my Thiel CS 3.7s at the moment.
I'm not sure if i should upgrade, anyway if i do so i'm looking for a used integrated amp in the $2K to $3K price range with balanced inputs.
I've seen a Sugden IA4 for $3K and a Musical Fidelity KW 550 for $2,4K but it's not balanced.
If i upgrade it would have to be really worth it otherwise i'd rather keep my CAP-151.
I have someone who would like to buy my CAP-151 for $1,6K.

128x128thieliste
Do you plan on listen to the amp first, or are you going to take a chance and hope for the best? Also, you should list your entire system because it makes it a lot easier to recommend something you'll be happy with.
Well it's not going to be possible to audition gear on the used market.
My source is a Hegel HD12 streaming music from Qobuz via USB.