o-rings?
 

whats the deal with o-rings and head gaskets?

An o-ringed head has a groove machined int he head where a stainless steel wire is placed. This wire adds extra crush to the factory head gasket fire ring.

you would basically do it for higher boost applications. (compound twin territory)

that said, I have had compound twins for 3 years pushing 65-75psi and I only have a stock head gasket and head studs.

no o-rings, and no fire-ringed head. (avoid fire-rings for daily drivers)

Same here. Hitting 54-56 psi with just a head gasket and studs with compound turbos. No problems in 2 years.