New speakers or new amp - your thoughts

room treatments might be a better investment, less sexy per se but probably rewarding.

after that, my personal bia is upgrade transducers as they have the most difficult job to do.

on your QB, which filter do you use ????
Have you downloaded the most excellent Ayre recordings jsing the Ayre A2D ? Reference grade stuff, IMO

You already have a nice system, so how about a power conditioner?
Even a modest oneac from eBay would help to protect the electronics and improve the sound (bigger one the better for smoother sound)

When you do upgrade, make sure it's enough of upgrade in sound and not a side ways move. 

I like Focals for their transparent highs - so how about a Krell amp?

Perhaps it's time to go separates if you really want noticeable improvements...

I just read specs on your speakers and amp. I recently upgraded from a pair of Focal Chorus 836V speakers to the 1028be which is driven by a Marantz Pm 11S3 integrated and I love the combination. While specs are not a substitute for listening to a system, your speakers are remakably similar specs to the 1028 and your amp  puts out 150w and doubles in output ( like my Marantz) to deal with the 100ohm dip Focals tend to exhibit  so I imagine the upgrades would need to be very dramatic ( and expensive) to make a significant sonic improvement. 

If money is burning a hole in your pocket perhaps consider these alternatives:

room treatment - as mentioned above most people ( including me) spend far too littl attention to this. 

GAIA isolation feet. These are on my Christmas wish list as an easily reversible tweak that seems to get nothing but positive reviews.

A  second subwoofer ?

Merry Christmas 

bigger sub

My vote for room treatment above gear changes. Always! Check out the room kits from GIK Acoustics or similar. A huge amount of what you hear is the room itself, so taming it pays off more per dollar than any other thing you might do.