HI THERE,
I HAVE JUST BEEN INTO THE FACTORY TO CHECK ON THESE BOLTS.
THE CORRECT LENGTH IS 3.75" AND THE THREAD SCREWS IN .75"
WE HAVE NEVER(KNOWINGLY)FITTED A 2.9" BOLT.
WE WILL CHECK ALL CARS IN THE FACTORY AND AT DEALERS.
SHOULD U BE WORRIED ABOUT YOURS,JUST TAKE A WRENCH AND CHECK THAT THE BOLTS ARE TIGHT.
IF SO THEY WILL NOT COME LOOSE AS THERE IS NOT A GREAT DEAL OF STRAIN ON THEM.
AS U SAY,IF ONE WAS TO COME LOOSE,IT WOULD NOT CAUSE AN ACCIDENT,BUT IT WILL EFFECT THE HANDLING AND U WILL HEAR QUITE A NOISE FROM THE REAR.
THANKS FOR BRINGING THIS TO OUR ATTENTION.
STAY COOL,
REGARDS