Ok, I'm finally breaking down and buying my performance rig. The only thing I've decided so far was the Ampeg PR 410HF (I have access to a store demo for $500 even, how can I pass that up?). The only thing I don't like is it's rated at 4Ohms. I will be seeking a single 15" cabinet to go with it. Also I'll need the head or poweramp to power both of those. My questions boil down to this. Most single 15" cabinets I've seen are 8 ohms. Several of the heads I've looked at won't run under 4 ohms. So, do I buy a Stereo or Bi-Amp head? How would it handle the differential load? Does a Bi-Amp head treat both loads separately? If I run them in parallel it should work out to 2.66 ohms. Would I be better off with a Pre/power-amp rack unit (I'd rather not due to cost)? What single 15" would you recommend that would compliment the 410. I looked at the Ampeg SVT 15E and to be honest, shallow, and superficial I don't think it's asthetically pleasing with the PR410. Thank you for your time. FWIW, I'm trying to keep the head and 15" under $1000.00 total so I'm probably going to avoid the pre/poweramp setup.