I agree. The angle grinder rotation is just too fast, even with a good flap disk. There's a reason why a tiny high spot of metal turns black even when carefully using them. For the record, I love the flap disk but I still haven't had a flap disk used on a variable speed angle grinder where it won't destroy everything in its path, and far as I know there's only one angle grinder out there that has variable speeds. I too think a mud hog with 40 grit works well but I also think it takes too long at times. If I use one it will be for the hood, roof, and decklid only on really low. Heck, I even strip them with buffers with no problem but you have to be REALLY careful doing that. Even on the lowest settings you can heat a hood to where it will appear to oilcan for a second but tighten back up with no noticeable warpage, more like just tightening it up like a shrinking disk, which actually is good. This will happen 1-2 times if I strip a hood with a buffer, but you gotta be really alert and mindful cause if you stop it at the point where it first starts to stretch and aren't butch'n it/hammering it you'll be fine and it will actually tighten up the flex a tad, which is usually needed anyways, but if you miss the first cue and keep adding heat you're heading for trouble. It also depends on the hood...If it's a huge POS with no supports and is flapping all over the place I'm not touching it with a buffer or anything aggressive.
Bottom line, I wouldn't suggest anyone stripping a hood, decklid, or roof with a buffer just cause I do it, and I think Martin has the best and safest suggestions.