Im not real familiar with all of 3M's stuff, just be careful what you use prior to a polish. If its a glaze, chances are it will be removed with BF polish. Your going for a good combo, using BF. Try to top with a carnauba the next day after using the sealant......
Yeah I don't care if the 3M is removed by the BF... I just want to be sure the PI-III MG is fine enough to use as the last step that has any abrasives in it on a black vehicle.
If you use BF Polish it has light abrassives in it. I went from DACP to BF polish and got good results. You may not need to top Blackfire APP, it looks good as it is.
The reason I suggest a Carnauba topper isnt for added looks, as far as Im concerned, you cant top BF with anything and make it look better. The stuff is totally awesome, but it tends to attract dust until some oils have evaporated or washed off, then its even better. The Carnauba will assist in eliminating dust attraction.....
Well its more so than the Bf polish, and Im not sure about the 3M PI, but you said you has some minor swirls, thats why I even mentioned it. 3M SMR is great stuff for light stuff.....Why dont you try the BF polish and see what happens, then go from there.
Now that I think about it, im a lil confused about the 3M PI-III MG...Isnt that a glaze ?
The beauty of BF AFPP, is its layerable....I normally go with 2, about a week apart, and of course thats on my own vehicle. Time does not permit that on client cars. 1 is satisfactory on client cars, but I will try to follow up with another at there next appt. in 3 months. Something else i love to do is put a second coat on before wiping the first off. It helps alleviate any missed spots, and just evens out the surface.