Shropshire-Guy

Anyone please tell me how big of job to do Head Gaskets on Legacy Turbo . Have done normal engines but never Flat 4. Im losing about a cup full evey 10 days to im guessing thats the problem. Carnt see any leeks at all and i think its on Exhaust side as Oil is spot on (hasn,t emulisfied) Any help gratefully appreciated or has anyone had Dealer do it ? If so how much ££.

Cheers

Steve