Reverse was also tight on mine in the beginning, after about 1K it loosened up.
CD
Are you doing alot of towing? If so, the G-56 is a great transmission. But, if you plan to heavily mod and drag the truck, then you are better with the auto (yes, you'll be modding that 48RE to handle the power). There is no comparison at the tracks, the autos are just faster than the manuals.