A lot of guys who race use them, I use them on my 99 mustang with no problems... From what I've read the biggest issue is the length of your wheel studs, as you shim the wheel out you shorten the available number of threads to clamp the wheel and the shim between your lugnuts and the hub. I read a lot of discussion on road race forums before I shimmed my mustang, and the consensus seemed to be make sure you have at least 6 to 7 full threads on the wheel studs that your lugnut can thread onto completely and to make sure you properly torque your lugnuts and recheck them after a few trips... I drive tankers for a living and we retorque our lugnuts after a day or so and you'd be amazed how many of them have loosened up!!! It is equally important that you don't over torque your lugnuts and wheelstuds as you can stretch and weaken the stud, causing it to fail under stress. Almost every wheel stud I've ever seen broken in 15 years and over a million miles has usually occured within a few days of a rushed mechanic with an air gun overtightening the lugnuts...