I have a 2001 BMW M3 in need of replacement Catalytic converters. I wish to go with the European edition BMW M3 CSL system....I think? After a lot of research I have found that the SUPER SPRINT STEPPED HEADER replacement pipe and 400 cell count catalytic converter has higher gains than the CSL M3 header pipe and a larini catalytic converter replacement. Both have cats further away from the engine. Does any one have any first hand experience in switching up a USA Spec M3 to accommodate these kinds of modifications? I have no idea if this is just a bad Idea and I should stick to USA factory spec replacement parts. I know the 02 sensor will need to be rewired for length due to the new placement of the catalytic converters being further away from the motor. BMW MOTORSPORT DIVISION IN GERMANY contacted me and let me know about 2 of the last BMW M3 E46 Race car headers that they have in stock unfortunatley I have no way of figuring out how to make those run with the current USA engine management system, I can do a stand alone. Not sure if its worth all the money in this current economic sittuation?

Go with the Supersprints. Its a quality product. Although, I would ditch the cats all together. They just get in the way.