I've had these on my car for about a month now and they are a little to loud for my liking for everyday driving and have a odd sound when the car goes to 4cyl mode. I've heard these on a GTO and they sound really good. These are still on my car right now. They are 2 1/2" in and out and both center. Looking for $140 or looking for another set of mufflers. But I'm really leaning towards the 3331 Spintech Sportman Series since they are a bit quieter.