Well I've pretty much made up my mind to go with a QSC power amp. But I still have some questions about the different models. What's the deal with the RMX HD models? Being optimized to run at 2 ohms or 4 ohms bridged sounds great, but why would they need an HD model unless there were problems with the non-HD models? How do the PLX series amps handle running 2 ohms / 4 ohms bridged? As good as the RMX-HD, or not? Lastly, how does the sound quality compare between PLX and RMX-HD? Which has faster response time and which is punchier? I really don't care about the weight or fan noise of either one. Mostly looking for good reliabilty running 4 ohms bridged / 2 ohms a side, and sound quality. Thanks guys!