will a 99 SI catalytic converter work on a 00 itr motor n ecu?

 

I'm going to say no...

 

as long as length is same it will

 

thanks for the input, time to start the search for itr catalytic converter now.

 

I didn't compare them back to back, but I recall my Si cat being shorter than my ITR. Given the cost of the unit, I would highly advise looking at other solutions for whichever purpose you need.. eg aftermarket highflow or resonator for rasp elimination, o2 sims for CEL, or an aftermarket cat or love of polar bears.

The money is probably best put toward security enhancements. I myself have been considering a camera for the garage..