All european games are the same. There are only 2 editions, Normal and Collector's. The Signature Edition (SLS Competition) has the Collector's Edition game and a bunch of hardware (key rings etc). The competition is just a code we got wth it.
The difference between the collector's and normal is the code for the chrome cars which was included in the Collector's, and a book.
I think Americans who 'bought' codes here at GTP (usually in exchange for cars, from people too young to enter the competition) have successfully entered the competition, but I don't know this.
Anyone?