Integrated upgrade recomendations

I like the Marantz PM8006;  I had a PM8005 for several years and was very happy with the overall performance.  Received almost full value as a trade in.

https://www.marantz.com/en-us/product/amplifiers/pm8006

Just went through this got  a Rotel A14

very happy 

powerful

great  sound

tons of inputs and outputs

The Sprout is bright and the Wharfedale's are dull. If you are keeping one as part of any future upgrade path then bear in mind you like the current sound.  If you replace one of them, do so with the same characteristics. If you believe you will upgrade both in the future either do it now or pick the one with a more neutral balance. Cheaper Marantz amps and dads tend to be bright. Rotel and certainly Creek tend to be more neutral. Musical Fidelity are rather more hit and miss some great others not, some bright, some dull. If you can afford then Naim are my preference of the well known brands, with NAD a good cheaper choice.

Naim 5si...$1699. 

What size space, main music system?

I would use those speakers in a second system, and get new larger speakers if the space allows. Or, no 2nd use, sell them to help pay for the speakers you move up to.

I use and very much like my Wharfedale Diamond 225, similar driver sizes and efficiency, in my office (with a single sub adding just enough that they don’t sound small).

your interesting amp does not appear to have pre-out/main-in so not ideal if you want to try a stereo pair of self-powered subs.