Adding Home Theater To 2 Channel System


I have a two channel system that I am very happy with located in a dedicated listening room.  I am considering how to add home theater without giving up the two channel sound that I enjoy.  My main speakers are Avantgarde UNO’s (horn speakers - 18 ohm, 108 db sensitivity). Avantgarde does not make a center channel speaker.  I assume that I will have a problem matching any box speaker center channel speaker with the Avantgarde - my worry is incoherent sound.  Is this something I should worry about?  Are there center channel speakers that might be a good match (I have been unable to find any obvious candidates ohm/sensitivity match)?  Is it likely that I will need to find a new set of front speakers from the same brand as the center speaker?

The rest of my setup: Pass Labs XA 60.8, Audio Research Ref 6 preamp, SME 20/2 turntable, Lumin x1 streamer, Ayon CD player, REL 812/S subs (2)
chilli42
I solved this problem by positioning TWO centre channel speakers next to the TV, between the main L and R speakers. Those two speakers were smaller versions of the L and R mains. Two more small speakers for surround speakers, and I had HT when I wanted it and two channel when I wanted that.

Those two smaller speakers above and below the TV is an even better solution if that can be made to work. I moved to that before I moved to separate dedicated HT and 2 channel rooms, and it's better. But a compromise is possible too. 
You’ve gotten all the advice there is so far. I will add mine. You have a highly evolved stereo. To add video to your room, make sure you don’t upset the acoustics you are currently enjoying.  MC is spot on in his observations. No Center speaker will blend nor is one needed. Add the Swarm. Get a 7.2 channel AV receiver for HDMI switching and to generate rear output channels, and get a pair of wide dispersion speakers for the surround channels. Ohm Acoustics might be ideal. Rig your own HT Bypass by finding the unity gain position on your SP6.  Relax and enjoy the best of both. Run your sub array off your stereo preamp, and set the receiver mains to large with + LFE. 

@bwguy. OP has dedicated listening room so I think the space is not an issue for him. The cost of home theater staff usually is not so high. Advantage of separate system for HT is pretty obvious. All in one compromise 2 channel and you don’t want your littering experience to be stigmatised by that. 
I for one like listen to music in the home theater room. I often game (online multi player) with the sound off and music on. 
 I am all for a combined system. You will not lose anything. Just gain experiences. 
I agree with MC. Don't do it. I did it in reverse. I had a dedicated home theater set up and I tried to integrate a two channel system into it. Miserable failure... lifeless! The answer was to have both, a dedicated home theater system and a dedicated two channel system separate from each other. I now enjoy the virtues of both for their intended purpose and I am much happier with the results.