Bolt on, no weld needed, with exhaust flange that bolts to exhaust manifold flange. Brand New, just out of the shipping box it came in. Was purchased for a vehicle that was totalled before I could put it on. These usually go for $120-$240 dollars, and you will not find this deal ever again. It's even worth to buy it for resale. I have been sitting on it for a long while and am tired of looking at it and being reminded of the moron that ran a red light and destroyed the car it was for. Please do not contact me if you are not going to buy it, I am tired of the window shopping. Also, please do not contact me asking things like "will it fit on my porsche?...how about my 2 stroke?". Come on with the bulls#!t. Hurry up and buy.