Gum Gum Fruit, also called the Gomu Gomu no Mi, is one of the most featured Devil Fruit in the world of One Piece. It was eaten by the Captain of the Straw Hat Pirates, Monkey D. Luffy, who aims to become the King of the Pirates and find the One Piece.
Gomu Gomu no MiWhen he was 7 years old, Luffy unwittingly ate the Gomu Gomu no Mi, a Paramecia-type Devil Fruit, after finding it in a chest owned by the Red Hair Pirates. It gives his body the properties of rubber, allowing him to stretch, bounce, bend, twist, and inflate any part of his body.
SSJ2 Gohan DID use his full power against Cell SSJ2 Gohan DID defeat Super Perfect Cell with his full power. The fact his arm got injured just made Gohan think he was down to half of his power due to his special confidence problems.
Ultimate Gohan was able to stand against Super Buu, which happens to be Buu's second strongest form. So this definitely makes Ultimate Gohan stronger than Goku SSJ3.
Goku SSJ2 (10*FPMSSJ) = 7,500,000,000. Goku SSJ3 (50* SSJ2) =350,000,000,000. Goku SSJ4 (50*SSJ3) =17,500,000,000,000. GOKU SSG = 20,000* POWER ABSORBED THROUGH RITUAL( 5 OR 6 TIMES SSJ) =15,000,000,000,000.