I currently have a pair of RTi70's as my fronts. I want to purchase as set of RTi8's and move the 70's to my surrounds. I am upgrading to a Pioneer Elite VSX-56TXi 7.1 receiver and will be using my current surrounds, R15's, as my rear right and left surrounds. I am not sure if I should leave the 70's up front and use the 8's as the surround, or sell my 70's and go with a set of RTi4's as surrounds. Eventually I will be replacing the 15's with 4's as well. Any suggestions or comments would be appreciated!!