Konrad

I have a 1998 Outback DOHC EJ25D that has 270,000 miles on it. I took it to a shop and had the radiator fluid checked for CO2. Low and behold, CO2 was found. (It has been blowing radiator hose along other head gasket issue indicators) I am planning on tearing the motor down to replace the head gaskets. I am wondering if I should do more to the motor once I have it out. Would replacing the main bearings be advisable? Is there anything else that I need to replace with I have the engine out? Is it even advisable to replace the head gaskets with this many miles on it? Details, I am the third owner. The first owner kept track of every thing that was done with this car. The head gaskets where replaced at around 80k. The second owner was a mechanic who maintained the car fairly. Since having it, I have put 40k on it and replaced several things, rack and pinion, fuel pump, time belt, etc.