i doubt that cdt has a better midbass response than the resolution. i just switched from mbquart to cdt and the quarts are louder for midbass. i will have a peerless midbass set installed in the doors, it's on its way . i've heard a lot of good things about this set.
i've heard the rmb8 set and like it but i dont want to make a hole in my door so decided to stay with 6.5. rmb6 might sound just as good and it matches nicely with your resolution.
Denon - PPI - JL Audio- Image Dynamics - CDT Audio - Hugfen