Rental Car advice: if you are flying into Dublin and spending a couple days there, I found it easier and cheaper to rent a car in Dublin than at the airport. The reason is this: Dublin is very walkable, so you would be paying for a car that will likely sit most of the time you are in Dublin. Can take a cab or public transit from airport to Dublin, and then when you are ready for the rental car, take a cab over to rental place.

I also recommend spending the extra $ and getting an automatic transmission. I drive a standard in the US but it was one other variable i wanted to remove, as driving on other side of the road was challenging enough at first.