From my understanding the KEF's are stand-mounts, so stands are definitely needed especially if you listen anything close to near-field. Very few stand-mount speakers are designed for anything but use on stands to avoid muddy/mushy bass. Suggest the stands allow for tweeter height to match ear height at your listening position. If you have pets or kids around, recommend heavy/wide based stands to avoid tipping over (I had a 5 pound cat knock over 10"x10"x20" speakers on 12" stands and 15 years later a 4 pound cat knock over much smaller speakers on 24" stands).
For that big of room, recommend use of subwoofers with any stand-mounts. Recommend reading Floyd Toole's "Sound Reproduction" to get a good idea of how bass behaves in-room. Based on his recommendations and your room size, suggest you look into using at least two subs set up at opposite ends of the room. Also suggest crossing over the sub well above the F3 of the LF/RF speakers (stereo mains) to blend well, take load off the woofer, and allow for mid-bass "body". One octave higher would be a good starting point. Much above 80 Hz and the ear can start to discern where the sub(s) is/are in the room.
If the sub is used for music, most recommend a smaller/sealed unit for music and HT use. Music subs should be "fast" and "tight" versus HT subs that do exaggerated special effects. Rythmik sells quality sealed units using up to 15 inch drivers.
With that low impedance on your mains, the power amp is recommended to have a "substantial" power supply and be rated down to below 4 ohms if possible. I've heard how a beefy power supply can really add meat to the bones of stand mounts. Note that the NAD house sound has traditionally been described as "warm". You're amp budget, compared to the rest of your gear is probably unrealistic unless you buy used. If you like Parasound, stick with that brand.
It's hard to glean pertinent information from reviews from unknown sources. It takes many hours of reading between the lines to learn the tastes, related experience, and knowledgeability of any given reviewer. For these reasons in my opinion Audio Review is one of the poorest sources for reviews, especially for higher end gear.
After 40+ at this audio seems that the upgrade bug is very hard to shake. HT is probably worse as the technology is changing faster.
