Nait XS2 as power amp or pre?

Hi guys, need some help making a decision here...

I'm currently running a Musical Fidelity cd transport into an Ndac, with external power supply. This then feeds into an XS2, followed by Proac D20Rs.

I'm of the opinion that the XS2 is not giving the Proacs the juice for them to really sing, so have been looking at replacing it. To say the sound is bad would be ridiculous, but I just feel there is something not quite there that I can't quite put my finger on. I think the best way to describe it is that I have heard the D20Rs sounding more lively.

I did consider the SN2 but am now looking at pre/power setup, particularly the 250.2. However to add one of these and a pre (maybe something like a 282), is quite a lot to spend in one hit. So my question is would I be better off going for a pre or power amp to use with the XS2 for the time being, until such time as I can resonably afford both?

Or maybe I'm off base altogether and the SX2 is actually considered a good match for these speaker?

Thanks