I'd go with Cell stomping here. Super #13's tanking feats were nowhere near as impressive as Cell's when he never took an amplified attack from Kamicollo with zero damage. I personally don't think Super #13 needs to even be on the level of Piccolo's Gekiretsu Kodan.
As for Genki SSJ Goku, he's vastly stronger than #13 when having perhaps the best tanking feat in the franchise, but I'd say bringing him up to the extent of being #16 tier is going a bit overboard. In a realistic fight, Goku would also only be able to throw one punch whilst in this state, so if Cell can survive it as I believe he would, Goku would lose. Also, Cell can just Taiyoken and Life Drain for an easy win.