Luffy's Grear 4th - Luffy turning into 'red' not pink(which is in grear 2nd- "PINK LUFFY" ). At this stage Luffy is very hot, even Aokiji(the ice dude) will be no match for Luffy. He also possess greater speed compared to grear 2nd and also incredible strength which is equally or maybe surpassing the strength of his grear 3rd. Hope you may have an idea of what I am thinking.