You will get a lot of hate for what you just did but to each its own. EJ20 is not an STI engine, it's a WRX engine. As for the intercooler I can't tell you but you can look at the scoop, if it has a spliter then it's from an STI, if not then is a WRX. I am sorry to say but you got scammed. You probably have a WRX with a tune.