I picked up some (a lot) at Best Buy a week ago in Ontario.
Had 3 types. The Japan + and -, and the Taiwan - stacks in 50 cake box.
I'm running Qscan on a -r Taiwan ProdiscF01 right now as I was reading your post.
On EW162i 47N9 (external)
This disk at 12x, 8x, 4x, 2.4x were all above the TE line near the start, the worst being 8x.
The next disk passed at 4x, but not 8x.
The Japan dvd-r TYG02 passed at 4x, but none so far passed at 8x.
The Japan dvd+r Yuden000 passed at 4x, and 1 out of 4 at 8x.
The Japan ones definitely scan as better, but I will be setting the speeds to 4x when I burn any of these Fuji I guess.
I'm still scanning, and have a lot I can sample from