I using them with Meg's 105 right now with my Flex 3401 ROB and I couldn't be happier.
Here's a pix of what I did on my mercedes using the PFW for about 1 to 1 1/2 minutes followed by a white ccs & 205 for about 1 to 1.5 minutes. (I didn't time but wasn't long.)
When I have time, I'm planning on taking a brillo pad to a junk panel I have again and testing it there. I had great success with the PFW and my 3403 & M105+205 White.
I want to verify I can get that type of stuff out with the 3401.
Unfortunately, all I've got now is an older Griots and an older PC. I do have a cheap Harbor Freight rotary to try. Maybe I will strap it on and practice on a POS driver or the lawnmower or tractor. My wife will definitely thin I've lost it!