Stereo Amp

- Parasound JC5
- Pass Labs x250.8 (used unit goes ~6K)
- McIntosh MC452
- Anthem STR (amp only)
- Rotel RB1590

My preamp: Arcam AV860
My speakers : B&W 702s2

=> Before you flame me, I'm fully aware that both the pre-amp and the would-be amp retail for more than the speakers themselves and it's not the logical upgrade path. Let's just put that debate to rest, please. I will likely upgrade the speakers down the road but I'd like the preamp and the amp to remain. So for now, this is what I have to work with

=> What I want to achieve : play the fronts full-range, sub-less, with CLEAN sound, TIGHT and CONTROLED bass. The 702s2 CAN be played as such and sound very good. They do require some fine components up the chain to do so. B&W can be brutal in that regard. 

=> What I have now: as good as it is, the A21 isn't cutting it. sibilence and not enough juice to drive the woofers sub-less. Close but not quite. The JC5, which I've demo-ed with the 702s, does a great job at it and is my runner up as it stands.

=> My other specifics : 
- 80% music / 20% movie (I do have a Velodyne sub to reproduce those earth shaking LFEs)
- room size: 25x15
- music genres: jazz, lounge, some electronics music, pop.

=> I located stores that will demo the MC452, the Anthem STR and the Rotel RB1590 with my same speakers. I've heard the JC5. The only unknown is Pass Labs x250.8, save for the fame: from the reviews alone, it would seem like an easy winner. but I've never heard one. Anyone ?