YBA Integre DT or Naim Nait 5

If you are looking at a Nait 5 and not a Nait 5i, you will have to figure on Naim speaker cable and DIN interconnects.
Nait 5i and 5i-2 can accept RCA interconnects and any speaker cable.
That said I think Naim is fabulous, and will work well with either of your speakers.
Not familiar with YBA.

I have not tried the Naim Nait 5 or the latest Naim amplifiers but have listened to other previous generations of Naim amplification products extensively and compared them directly to YBA.

If you like the YBA sound then just go for it. If the current Naim amplifier products are an evolution of those of previous years then YBA would be my choice.

YBA has a much more natural and open musical sound with superior timing and fluidity. Naim seems to ALWAYS produce a grip on the music and tends to ALWAYS have a beat which can sound impressive at first but in the end it is also a bit artificial and tiring in my view.

A couple of friends, both big fans of Naim, converted to YBA products without any hesitation whatsoever and never looked back.

Good luck with your choice.

I would allways recomend mating french electronics with english speakers and vice versa. French electronics, particulary YBA have fantastic timbre, 3D, musicality; and english speakers tend to be on analytical side.