If the stud breaks off, you can center punch it and drill it out. You may have to take the exhaust manifold off though if you have no room to work.

Usually with the motor mounts, you can take the fan shroud loose, take the motor mount bolts out, and then get a solid piece of wood that GOES ALL THE WAY OUT PAST THE VERTICAL EDGES OF THE OIL PAN and jack up on the engine to raise it up. Of course if you have a engine hoist, you can lift it up a couple of inches with that.

What are your intentions with this truck? You are correct, improving airflow will increase the power output, but it won't do you much good if you are towing a heavy load down the highway at 1500-2000 rpm.