I built my dana cheap and it don't flex period. less resistance than a 9 inch also..I paid150 for a 4x4rear 4.10gear, 200.00 to narrow with big bearings and 8.8 brake housing ends, 510.00 for spool ,35 spline axlesand bearings . I think 860.00 for a race quality rearend that I could put in a 700 hp 4000 pound car will survive well under my z. If street driving is desired then a different locker would be needed but they can be found .