Not hard, just prep prep prep, Sand fill, sand high fill primer, sand some more, block sand. Get a good quality gun, good compressor, dryer, and go for it. If it looks bad before paint, it will look lots worse with paint.
Yeah....No... Keep that sanding $hit.. The first , and only one I did was the engine bay in my GTS. Never want to see sandpaper again... Ohhh GEORGE !!!