I'm not local... I live in KY. I don't remember what the diameter is... I need to check the paperwork for the work I had done to figure it out. Right now my car is in the shop, so I'll have to wait. I think originally I spent $370 for the custom exhaust. It was a fairly cheap setup. I guess I'm way off base by saying 3.25 inches... It was a long time ago that I had this done.