Don't forget that the SR20DET engine has an Alloy block and timing chain, while the CA18DET has a Cast Iron block and a cam-belt.

Also, the SR20DET does muller cams when the oil changes have been neglected leading to blocking of the oil spray-bars, I think it was that which Tony was referring to.

That type of neglect is what causes them to destroy big-ends and also VVT pulleys (in SR20's).

The thing is, they were generally used by business men as a high-end sports-tourer and as such suffered poor servicing. It is only 2nd user onwards that they fell into the hands of enthuiasts, but for some engines this was too late.

Really the head gasket becomes a concern after 300ish bhp and really wants replacing with a thicker Metal one.