I can't afford to install ARB air lockers in both the front and rear axles, but would like to install at least one for now. Which would be better to upgrade - the front or rear? Also have a second question: I was thinking of installing Newfield birfs. My front axle was changed sometime in the past to disc brakes. The locking hubs look like the Warn hubs Toyota supplied on 76-78 front axles. There is a small stamp on the hub - H193. Does anyone know if these hubs are 6 spline or 30 spline? From what I understand, the newfields can only be installed if the hubs are 30 spline.