if you say its worth half the price, i would crack the shits if someone sold me a gtr and it turned out it was a gtst
but if its not like that, umm.. im trying to think of what it would be,
but yeh it depends on how much its worth, if the genuine one was only worth 10 grand and the one you got went just as well i wouldn't bother, but if its a 100grand r34 gtr then thats different