JDookie said:
I wasn't thinking that MG had any abrasive qualities to it at all. I think this is why I usually skip the MP step that you like to use, I just don't see enough difference. Give me a scenario where you would use MG, if you don't mind.
Well, the PI-III MG does have cut, it's just pretty mild. It can *really* accomplish some things by rotary, and on not-too-hard paint it works well by PC/Cyclo/hand too. I was thinking earlier how it really is a good bit more aggressive than the 1z MP.
Back when I had the WRX, the PI-III MG was about all I ever used on it when I needed to remove marring (and I used that car year-round and washed it with a BHB, none too gently, either

). When I do the MPV (after a year of washes with the BHB and two years without polishing), I'll probably do 90% of the work with the PI-III MG, and there's no way that using something as mild as 1Z MP would accomplish anything significant.
The final pass with 1z MP is a pretty subtle improvement, but I find it so easy to do I always add that step when I'm using 1Z stuff. If you're happy with the way PP leaves things, then sure, skip the MP.
But IMO you'd be missing out if you don't get the PI-III MG because of a perceived similarity to 1Z MP.