How hard to change head gasket on a 92 3000gt vr4?

If its leaking alot of oil should i try to fix it or sell it...Is this engine, 6g72 hard to fix?? II know they are expensive but are they easy to mod or fix on??|||well it will take u about 4 days to do it your self depending on how handy you are with that kind of stuff and between 300$ and up|||a head gasket will not cause a oil leak.. put some cardboard under the engine to catch oil and then you know where to look make shure the cardboard is under the transmission to