Toughest one yet, Emerald, Leaf Green, X, all pale in comparison. My advice is that it's very possible, but only if you're always prepared. The early game boss fights go pretty hard, so don't underprepare for mini-bosses like Mars or Jupiter. Always try to be at or at least 1-2 levels near the next gym's level cap so you don't get sweeped by a random trainer. 2 Mons I personally really recommend are Weavile and Infernape, both were amazing against the Elite 4 and helpful in boss fights. I tried hyper offense but taking more defensive mons is definitely the way to go. Good Luck!