i use colormagic on my car, obviosly the black stuff as my st is black, its really good for covering up the stone chips.
i t-cut my car at first then polished and waxed it, it came up like a mirror, was really good finish, now i just wash polish and wax,
machine polishing gives good results as long as you know what your doing!
holding it on can reck ur paint, as heat dispereses differently through metal and plastic, so you could damage the paint, burn it etc.