Which center channel?

I have dynaudio audience 52 for fronts and audience 42W for rears. I am trying to decide if I should go with a 42C or a 122C for the center channel. I watch about 70% movies so I would like something that sounds really crisp like the fronts. Would it be better to stay with a small bookshelf speaker like the 4 ohm 42C or go with the 6 ohm 122C? I am using an Outlaw audio 7125 amp to run the speakers now at 4 ohm so would need to integrate the center into my system.

Can anyone suggest a center channel that would sound good with my current setup in case I want to look at a different speaker? I know it is best to stick with the same speakers all around but there may be other options.

I would go with an Audience 52 on its side.

Stick with the same speaker. Use a 52 if possible or go with the 42c which is a very close match and actually designed right. If you can only buy 52's in pairs, then use the second one for center rear channel.