With my experience, you are correct. WOPC should only be disabled when the media can support it (ie, if it passes with wopc enabled and it is quality media and you want to over ride the strength of the laser).
The scan you have posted shows me that there is a problem with your system/media and not the burner. Have you checked the DMA settings for the new drive? Also do a defrag of your hard drive that has the image as temp storage. Make sure that the benq is set to master on its own IDE channel, it doesnt like to be slave to another burner. I know you are using a good power supply, but you might want to ensure it has its own 12volt leg with nothing else attached.
Also do a fresh Firmware flash.
Dont give up so easy as many have before, I think once you get this figured out you will be glad you did.