My friend recently broke the main gear shaft in his Saltist 5000 on a 20kg GT, his txt to me was "Saltist 8, GT 1" - he had caught 8 GTs up to about 25kg over the last 4 months on it, and managed to break it while fishing a max drag of about 8kg, with 65lb braid and 120lb leaders.
He has since upgraded to a Saltiga 6500 but it will be solely aimed at GT popping. I think the Saltist was good for general purpose fishing targetting mid-sized fish but if you are consistently pushing a mid-range reel with 20kg + GTs then something probably has to give.