What's the difference between these two products? I have a bottle of SMR for dark colored cars, because I used to have a dark blue car. Now I have a silver car, and was wondering if it's ok to use?
The difference is in the colour of the fillers. If you are going to be cleaning the paint after the SMR, such as with #20, or AIO, it would be ok to user the SMR for dark cars. If not, then you'll have to wash the fillers off with Dawn.
I have been told that 3M SMR for dark cars is slightly more abrasive than for light. I have yet to get a clear answer from 3M about it, and my tests really are not technical enough to see the slight difference that I was informed of.
Since I end up stripping off the fillers with AIO on the cars I detail anyways, I simply stick to "for dark".