i'm led to believe that the old studs are breaking due to age, heat cycling, and re-use. If you change the studs with the timing belts, you I wouldn't imagine any problems with them. There's quite a few stock studs over 200k miles with no problems. You'd think that it they were a weak point, they would have shown up long before now. Honestly, i don't think it's worth the hassle to try to find another stud to use when it's cheap and easy just to go OEM.