haha you fool. you can get platinum by getting all the trophies of the original game. this counts fo all games, and burnout paradise.
so you dont need to get the party,legendary,boost special and island trophies to get platinum.
i lol'd
EDIT : make sure you've gotten ALL trophies in the original, there's a chance that the cagney update counts as well, altough i dont think the cagney had any trophies.