I have been using spidertrax spacers and have been doing some hardcore wheeling with my friend that owns a 07 FJ Cruiser on 35's with spacers with no failures to date. Its all about how you torque them and the company you go with. My spacers are torqued to 90 ft. lbs and the wheels are torqued to the spacers at 90 ft lbs. They have been installed 3 years now and have never found loose lug nuts or broken studs. I know 90 ft. lbs isnt a lot but it works for me. It came right off the installation instructions from spidertrax.