Looking for an integrated amp around 4000 to 5000.

@pal   

I am looking for a greater sense of presence in the music. More body in the vocals and space between instruments.

This part is very helpful - now we understand what you're looking for.  I actually think your speakers are holding you back from achieving this much more than your amp.  Those Ascendo C8's are not necessarily the fastest nor the most dynamic (particularly at lower volumes).  I would opt for a speaker change before considering an amp switch.

@pal As @klh007 asked, what can you tell us about the sonics you’re seeking in an upgrade that you’re not getting from your amp? I can’t believe (well yes I can) people are just recommending gear left and right without even understanding your musical priorities. People will always just recommend their favorite brands or what they use themselves without listening to you or asking probing questions.

Can you describe the "change" you’re looking for? If you are simply looking for a change then that’s easy - just buying something else....anything else.

And why do you need a line out for a sub?  Many people find it sounds best to simply connect to a high level input on a sub.