Hi LMB, yes the ep3 back box did need welding. I took it to a garage and they cut the connector off the old exhaust and it was welded on to ep3 back box, as the ep3 back box would not bolt on as the diameter was larger than the oem connection. The hooks holding up the exhaust also needed to be cut and lowred for a neat finish. The back box cost me around 60 pounds from eBay, the welding and fitting cost 40 pounds.