I was going to buy the RM7200 set but noticed a lot of people buying better speakers after about a year of use. So i've decided to skip that stage. My question is should I buy the FXI3 (Back), CSI3 (Center), and RTI4 (Front Bookshelves) together, or mix larger CSI5, and, RTi6 with the smaller FXI3's? If I used the mixed setup would this sound good? or should I sitck with all speakers having the same size driver?