Great 2 channel or 4/5 channels?

I have a concerning issue. I have a pair of amazing Casta model C's. An Audiozen 2 channel amplifier. On trial with me is an Audiozen Tube pre amp and tube dac. I also have a Core Audio Technology server with Flac files(USB stick). Music is simply stunning. Soundstage is large, dynamics are great, information through this set-up is world class to me.

On 2 channel with movies it is just as good. I presently use an Oppo 103 that needs to go as I find oppo to have very thin midrange and bass range-trade-off to the high resolution(103/105)they have. Just awefull. I was thinking of a higherend used pioneer or marantz with anything but an Ess saber chip.

I do have a matching pair of Casta D6 surrounds that are not hooked up as I do not have another 2 channel amplifier and a processor for channel processing and steering.

My main points are: I definitely don't need a centre. I could use a sub for lower octaves than my Casta C's 15" woofer in each speaker just for movies. Music is palpable, chest tight, punchy and dynamic. My concern is utilizing my rears for that surround fill-in but would mean downgrading to pre processor for the 3rd and fourth channels. Once I pull the dac and pre and add a processor, I lose that 20-30% of information.
Or should I stay with 2 channel for movies?
It seems to be a trade-off with a processor as it sucks all the positive points from the 2 channel set-up. To me surround/side information is critical in movie watching, and my surrounds have crazy information from the dipole setup. I am trying to get the best of both worlds here but it is really not possible unless one has two seperate set-ups in two different rooms.

If anybody has any suggestions on what I could do or use as a processor and universal bluray player for both worlds it would be appreciated. I don't yet have a budget but it isn't an issue.....thx in advance.
I don't fully understand your setup. If you're using an Oppo as an analog source, it should be a 105, not a 103. A processor with bypass would give you the best of both worlds. The front LR of surround could use your current stereo setup with the surround channels from a processor going directly to amps.

In my setup, output from DirecTV HD-DVR goes via HDMI to an Oppo 105 connected via HDMI to a Cary Cinema 11a processor. Stereo goes from the Cary to a Parasound JC-2 BP, surround directly to amps. The JC-2 is shared with an Ayre C-5xeMP and JC-3 phono stage. The Cary is shared by a Sony XA5400ES. For surround, the JC-2 BP provides unity gain and the Cary controls level. For stereo, the Cary and subs are out of the loop. I have used this scheme with the Oppo 105 serving as both source and processor, but I wanted mch DSD from the Sony that requires HDMI and a processor that can accept mch DSD.

Dbphd, will not use an oppo 103/105 for audio. I only use the oppo for HDMI video. That's it. I had a 105 and it was awful. I can't be more blunt. The 105's chip is very high in resolution but at the same time too thin and unbalanced - awful. I run the music via coax to server now and it is stunning. I am talking with core in regards to running my server with 4 channels straight to two of the dual mono Audiozen Noah amplifiers. I want no processing. When you listen to a system with no processing you will see what your missing. And once you take the processor and run a separate dac/pre you get 30-40% more information for movies and music.
Sorry I responded so ineptly. I must have misunderstood the last paragraph of your post.
I'm not sure how you arrived at your statistics and percentages, but have you considered a high-end pre/pro that runs analog (no processing) for 2-channel audio? Some McIntosh units could provide the best of both worlds. Unfortunately, McIntosh increasingly lacks the cache of more esoteric brands around here.
Aside from Mac, AudioResearch, BelCanto and C-J had good MCH analog preamps. I currently use the AR.