Just a follow up on the external amp mod. I was having some slapping sounds when there were gunshots in the movie I was watching. Thought I blew a woofer but it was the passive radiators that could not handle the dynamic power of the new amp considering the plate amps are supposed to be 300w and the Crown XLi 1500 at 330w. The Crown seems to have more reserve power for dynamics and had to dial them down to half volume. See the video below about the conservative power ratings of the amp. So I would suggest the Crown XLi 800 instead if attempting a external amplification.