2 Fast 2 Furious, The Subaru sound?

Now for all the grease monkeys who have seen 2 Fast 2 Furious,(I know that it was released a while back but it was when I didn't know anything about cars.) you've probably noticed that the Mitsubishi Eclipse Spyder's exhaust has the same note as a Subaru EJ series engine with unequal length headers,exhaust system etc, now I'm thinking: "Did they do an engine swap?", "How can you get an inline 4 to sound like a boxer?" I NEED ANSWERS!