Surely the most logical thing to do is to buy more of those new Intercity Railcars the "22000" units that Irish Rail have just purchased and brand them up as Enterprise and have them operating on that line.
That'd give 100mph service, which is more than adequate for that line without massive upgrading.
It's a short trip and will only require a very small fleet. It seems insane to go and buy another weird one off set like the Enterprise.
The other alternative, if they want 125mph service, would be a fleet from CAF with powercars that would match the Cork-Dublin sets...
No doubt they'll order something completely stupid though !
E.g. German ICE coaches hauled by a steam locomotive or something....