In my experience, there's very little difference between the Guinness here in the states and back in Ireland. If I remember correctly there was some Guinness being brewed here domestically however that changed and now all Guinness should be brewed in Ireland and exported here.
Wurm, not sure what you have available there but we get the Extra Stout version which comes in 12oz bottles. It is CO2 carbed like normal as opposed to the draught and canned versions which use the nitro widgets. My favorite is the Foreign Export version however I haven't seen it on the shelves in quite a while.