Honestly just get the ones from Alibaba, they work perfectly fine. Spending like 18,000 (with shipping and duties) for 500 watts is madness, you can get 1200 (true watts) for around the same price from alibaba. I had 5 320 watt panels, sold one to @master_g and still got 4 for my main tent. You can ask him about the performance of it. The only crappy thing about them is the dimmer unit, its crap. But I'm busy designing a controller for them and will also be writing the firmware, so when is done I'm more than happy to release the schematics or even build one for whoever wants one.