Upgrade advice please

Have lurked on and off for some time. I've got to the stage with my hifi where I'm a little disillusioned with the experience.

I have a CD3.5, Nait3R working as a pre-amp and a NAP90 driving Neat Mistique 2s via Chord Rumour cable. I've gradually found the setup more and more underwhelming. This is possibly partly due to the fact that I'm a film editor and spend a fair amount of time in dubbing theatres and am used to hearing large, controlled and detailed sound systems.

So it's time to upgrade. Having heard my brother's Rega and B&W 502 system, I went to a local dealer yesterday and listened to various combinations of Rega components and PMC TB1s, thinking my "budget" Naim system wasn't up to it. But actually the difference was fairly minimal, apart from a slightly more pronounced and musical midrange. But it wasn't until I tried the Exon monblocks that I began to feel the kind of heavier welly and control I'm after. But the sound certainly wouldn't justify an outlay of another £2000 (part ex-ing my gear aginst brand new Rega components).

So to cut a long story short, I returned home and had a listen to my setup. When cranked up, the welly was all there, but the midrange became confused. I'm wondering if the Neat Mistiques are letting the rest of the system down.

Does have anyone have opinions and advice on the best upgrade path? I'm going to stick with the Naim gear and am considering trading in/selling privately the 90 for a 180 and continuing with the NAIT3 (92) pre-amp. I liked the clarity and authority of the PMC TB1s but don't have any experience of using them with Naim amps - can anyone suggest a similar/better floorstanding speaker?

Also, would a flatcap power supply improve things drastically at this time?

Any thoughts would be greatly appreciated.

Thanks in advance,

Ben.