I just got a SWR workingman's 300 head and a brand new Hartke 4x10 cab. I'm still having a bit of trouble understanding ohms. Ok, right now my amp is sending 160 watts to my 8 ohms cab. If I add a 1x15 (8ohms) cab to that, my amp will be sending out 270 watts at 4 ohms, right? But heres my question, will my amp be sending out 270 watts to each cab, or 270 watts between the 2 cabs (135 watts to each cab)? Overall, how much louder will my setup be if I added that 1x15 8 ohms cab?