I have a 2002 subaru wrx, 110k miles, grimspeed control, 50/50 BOV, headers, cold air, it makes a weird clunking noise at start up, and than at higher rpm it isn't there. Than at idle I can hear the clunking noise as well, but sometimes i cannot. I can only hear it when I am in the car, when I pop the hood to try and find it, I cannot locate the sound at all. I have read the forum and have read many reasons, But some say it can be the starter? I have had an issue with the starter sometimes grinding but not often. Also, some say it can be a piston slap, but would you hear that out of the car? Also, when I turn the car off, it makes the clunking noise before dying. Any suggestions or comments would be helpful. Thank you in advance. This is my first Subaru and my first time to this thread. Just paranoid about the whole sound.