OK, I'll keep looking into the G450, but the more I look at the G5000 IPL the more clear it is that this the basic design on the Earthquake 45cc.
People always say that that these are copies, implying they are somehow illegitimate. It would be hard to imagine that saws sold at Sears and TSC as well as many other large chains are stolen illegal copies - I tend to thing Husqvarna would be all over that. RedMax was building the GZ400, which was a GZ4000 made in China, and Ryobi sold it too. Jenn Feng was selling a GZ4000 they built in Taiwan. I think instead that RedMax was licensing these designs, as they could not get their own sales volumes high enough to compete.
These Earthquakes are older G models, not GZ's and I suspect they have the rights to build them. So the Chinese are pumping out a lot of saws based on a very good design. It's ironic - Husky probably bought RedMax for the strato technology and somewhat for the name. They've left the GZ4000 and GZ4500 in the line up for now but everything else has now been replaced by a Husky or Poulan corporate design. But world wide they will end up competing against RedMax's old designs, which turn out to be pretty darn good.