WOW....they sound soo nice. I highly recommend that you get cutouts for mustangs, they sound really good on my car. I heard some people say that they sound like crap over 2000 rpms..... hell no, it just gets even lounder and more clear. Well thats in my car, but i wouldent think it would sound that much different in a GT. Im planning on posting a sound clip soon i just need to figure it out.