I just recently installed these Infinity components up front and have been pleased with them so far. The kappas you referenced will be even better, I'm sure.
I don't use the ceiling speakers and like you I don't have any in the rear pillars either and never really saw a benefit to putting any in. I have a 10" sub in a custom box above the rear driver side wheel well. So far, that setup has been plenty good for my ears. I also just finished sound deadening the entire rear, roof, doors and sides. Only thing I didn't do was under the front seats and the firewall. It's made such a big difference, I love it.