Yeah, I know. But he doesn't mention directly that he wants to keep the Benq firmware. The hex editor part can be interpreted both ways as well. Either he wants to use Benqs firmware, but wants the drive to appear as a Plextor, or he wants to convert it back to Plextor firmware. I guess your interpretation is equally possible, but I fail to see the reasoning behind it. To keep warranty? While it might make it a bit harder for Plextor to discover that the drive's been tampered with, I don't think it would make much of a difference.
Just my 2,