Hey Mate, I wouldn't think you would need a new box, maybe just needs a refresh.. If you want someone local in Brisbane to have a look, Clinton from Profile Autosports has done a number of simple rebuilds (Refresh) on the ZF's. This includes stronger input shaft and new clutch packs etc.. However, if you want to go further and look at a stronger/built box, unfortunatley there is nobody in QLD that can do this that I know of. If you want a built box I rate Rob from MTE work highly and has some of the most powerful Fords in the country running with his built ZF's. Cheers Ben