I was replacing my intake manifold yesterday and while torquing down the last nut the attached washer shattered. Proper torque value was used. I am going to the dealer today and getting new ones all the way around. Anyone considering r/r of manifold may want to get a new set.
While I had the front end off, I replaced seals for everything I could see, such as crank angle sensor, dipstick tube, the inner O-ring for the waterpump/block flange (mine had a small leak). Now I know to get new intake manifold bolts.

 

Look at MiniMadness site.
They have locking header bolts.
Alot stronger than OEM studs.

 

Mini Madness has exhaust header bolts, not INTAKE manifold nuts. (yeah I know I spelled "manifold" wrong, it was a typo)
Went to the dealership yesterday to find out the intake manifold nuts are not available right now, they are having to make new ones. I wonder what's up with that?
I will call around to a few dealers to see if I can find a set. I am going to replace all 5 I guess.

 

Sorry
Misread post
Old eyes
If you want really good studs, ARP has metric studs in various lengths.