The interface pad definitely makes a difference. I have a purple 3M pad on my clear coat DA, which is pretty soft, and forgot to use the interface pad one day dry sanding with 1200. It pigtailed bad, and I had not had any problems before that. Any good quality 3/16" da should work fine. Just make sure it and the hose is clean, so it won't drop dirt on the surface. I have several interface pads, but I like the 3M the best. They seem to last a little longer.