After reading up a post last night, i was determind to find out what engine i had. I fealt under the exhaust ports and noticed one was different (2nd in from right). I jacked it up, and held a torch up to see a nice little Coscast symbol.
Apart from it giving a lot less chance of the head going porous, what other advantages has it got? The engine seems quite quick compared to other non costcast standard engiens in other corsas.