Upgrading HT Receiver and Speakers

Hi All, I’ve been looking into upgrading my current home theatre system, and have spoken with some retailers around the area I live, and would like to ask some questions of actual owners if that’s okay?

I live in Western Canada, my bonus room is fairly enclosed at 16ft long (including 2ft depth shelving), 12 feet wide, and a 9ft ceiling.

My primary use is movies (around 90%), but will increase music listening with a decent system!

I am limited to a 5.1 bookshelf system due to pre-wired built in home entertainment center, rear speakers are in the corners, so no dipoles.

Retailer options in my area and product suggestions, prices between retailers have come in around +-$500 from each other:

Retailer 1
Rotel 1057 Receiver, B&W CM1's and CMC center, REL subwoofer, (or B&W 602S3's with matching center)

Retailer 2
Arcam AVR-300,Totem Rainmakers, matching center, and DefTech Supercube 2 Sub, (or def tech bookshelves?)

Retailer 3
Arcam AVR-300, Quad 12L front, Quad 11L rear, matching center, HSU VTF2 Sub

Retailer 4
Sherwood Newcastle R865, Paradigm Studio 20's front and rear, CC570 center, and PW2100 sub

Now the questions and opinions that I’d be grateful to hear answers for:
1) Which combination provides the highest level of detail without being bright/forward if you’ve listened to the above?

2) Cost vs quality benefit: are you paying more for B&W & Quad vs Paradigm due to country of manufacturer, and therefore would the similar price of the paradigms be indicative of better build quality and sound over the aforementioned 2? The same goes for the receivers, but I have been reading great things about the Arcam.

3) Has anyone compared the B&W CM1's to the 602S3's?

4) Why are bookshelves better on stands vs an actual shelf? Are there any recommendations to remedy this since I'm stuck with shelves?

5) I think we pay a little more in Canada due to lower volume sales than the USA, but how do the prices sound of the above combos compare?

I’m thinking it would be good to stick with one retailer as all have been very helpful when I’ve spoken to them, but they all (understandably) have their personal biases on the equipment they are selling. I will be calling them to set up demo’s to have a listen, but the better prepared I am with information, the better I’ll feel.

Thank you all so much from a former forum lurker……