Well, as much as the third gym was easy to deal with using Flamethrower, the fourth was a real nightmare! Getting to the gym was pretty easy and fast, if we don't include the time it took me to find Modest nature Slugma and Numel. Flannery is increadibly tough to beat, when you're using only a flamethrower! It took me about 20 retrys to finnaly beat her, even though my pokemon are all high level now! At the end I acctually lucked out, cause Slugma I defeted before that-cursed-Torkoal used Sunny day and my Slugma used it's flamethrower with a critical hit so it KOd Torkoal!
My team now...
Blaziken lvl. 38
Flamethrower
HMs
Slugma lvl. 29
Flamethrower
Rock throw
Smog
Harden
Numel lvl. 30
Flamethrower
Focus energy
Growl
Tackle
P.S.: To BlueShellBeast to get the Coin Case, go get the harbour mail in Slaterport (buy at Mart) and then go to Mauville. In the first (southest) house, you'll see a girl, talk to her and she'll trade her Coin Case for your harbour mail! ;)