I'm sure the performance will be hardly better than a relatively modified R34GTR. It's not not quite in supercar territory so its almost certain that it wont live up to the hype.
For the money it's a damn good buy for a standard car (even if its not quite able to show the Porka turbo whats what, its still under half the price!). As always, you could spend the same amount of money and modify the crap out of an R34GTR and get something that will be quicker everywhere, but its just not the same as having the latest and greatest model/variant/facelift model etc