Those B&Ws err on the side towards bright/edgy especially on treble unless matched with warmer more forgiving amp. The Parasound mentioned or a McCormack would be good on a budget...Pass later at higher price perhaps.
I'd rather you do DIY rack or even temporarily even cinder blocks etc in the short-term vs. keeping the NAD and buying a fancy rack.
For the room treatments, absorption or diffusion at first reflection point will be most impactful to taming those tweeters!
Cheers,
Spencer