I have really been considering finding a pair of sda's for my mains that would replace my rti70's. I just have alot of questions regarding if this would be a good move or not. First thing,would any of the sda's blend with my current spekers(fx500i side surr,rti6 rear surround)for home theater and music? Second i am a little confused as to what amp can you use with the sda's,i currently have a 3 channel sherbourn 200w x 3 at 8ohms,300w x 3 into 4 ohms minimum sine wave continuous output per channel, whatever sinewave means.The manual also states 8 or 4 ohms in normal mode or 8 ohm for bridged mode?Ihave heard that you would need a common ground amp, is this true?So would above amp do the job? what about the speaker cables,what would i need there?One last question for now ,how reliable would some of the oldest sda drivers be, being 15 to 20 years old, can you get replacement stuff for sda"s ?I really have never heard any sda's, but have heard they are a great speaker,it would be nice to have a pair of mains that would sound great with pure direct stereo and double for home theater .I realize that there are a lot veribles and questions here but if anyone could give me some feedback i would greatly be apprecative.