Saying "The one" is kinda wrong as they have alot of different spoilers. they have atleast 4 different spoilers that the customer can order..
and thats not counting the one on the GT but i'm sure you can get that on a stock :P
Actually i'm almost positive that they now make their own block (or have them made by the same company that makes the Bugatti's block and most of the Ferrari blocks)
without knowing anything other then make of the other car this is kinda.. pointless..
the other car might have been a 1989 LS400.. and as we all know.. cars from the 80's and cars from the 00's are not equal in safty..