I've yanked off the heads to my 98 RS, and I'm going to replace the stock head gaskets with the new 4-layer head gasket from Subaru. I was also going to O-ring the heads, but the guys at the machine shop said it's not necessary for low boost applications (0 - 10 psi), especially since I'm going with the new head gasket. He also wondered if this 4-layer head gasket is compatible with O-ringing (which I have no answer). So, here are the questions I need some answers:
1. Can I safely change to the 4-layer head gaskets, and not O-ring (again only running less than 10 psi)?
2. Is the 4-layer head gasket O-ring compatible?
3. Has anybody blown the 4-layer head gasket, and what boost pressure did it blow at?
All help is appreciated!