will i need to weld the downpipe provided with the header to the cat, or will it clamp?
It clamps on if I remeber correctly, just in front of the Cat.
better to weld it though, makes it a more stable and solid seal.
Maybe, but I wouldn't weld it. If you ever decide to sell the car and remove the parts, what do you think you'd get a better price for? a nice and shiny Header, or one that's been welded and cut off?
but if you cut it just right and re-and-re it, then you could still get the same for it.
You should welded It..I used the clamps...And it started to leak within a few days...Alos you are not welding the headder you are just welding the small down pipe thats is off the collector..So if you wanted to sell it you would not have that section which is ok because any good shop can make a new one..