you almost sound like you know what your talking about there, unless the person you are talking to knows what they are on about. First little flaw in your system, your running 6x9s on the shelf and a sub in the boot? You running the 6x9s on high pass crossover? In answer to the origional question, two tens work very well as some on here may know me and my old boot build. I had 2 vibes running 300w rms each (by the way RMS is the real messure MAX means fluck all) and they rock, but like said higher up the jbl subs arent bad at all. But if you are running a sub please make sure you amp your sub