Does anyone have any input based on experience with this... http://www.eastwood.com/fender-finisher-1.html

I'm currently on 18x8.5 wheels lowered on D2's. I cannot go as low as I'd like due to tire rubbing. My fitment isn't entirely extreme so I don't think I need to roll the fenders, I just want to get rid of the "lip" on the inside of the fenders and give it a shot. What do you guys think?