Does anyone know if there is any difference between the two? Size of tubes?

 

The collector flange will have a different angle because of the different cats. used, and the Si version is most likely shorter (height, not length) than the ITR because of the B16's shorter deck height. I would imagine tubing diameter is the same on all of DC's VTEC headers (JDM 4-1 and USDM 4-1 are the same), although I am not certain of this.

 

the tubing diameter on the jdm header has a 2.5" collector, and the usdm one has like a 2. 25" or something

 

So it should bolt up to my JDM B20B fine?

 

The Si version may not be tall enough to clear the oil pan.

 

Really Can anyone else let me know if that is true or not

 

Either way, I would run something with a larger collector on a 2.0 L motor.

 

I would recommend the jdm 4-1. Fits perfect on the b20b and youll love it.

 

i wanna get the DC jdm 4-1, i heard it hangs LOW tho, but it will fit on a b16 w/ some cat work