With the rear being the solid mounted diff would not it help to increase the rear stance of the tractor. If you have enough rear weight to compensate for the load in the bucket your rear axle would be the part that gives you stability. What i mean is if you dont have loaded tires or a ballast box when you max out your loader the first thing that happens is you lift a rear wheel. If you can keep the rear wheels on the ground then you shouldnt have a ballance problem. I would be concerned with creating extra stress on the front end by making it wider.