ok so i was looking on kteller.com and i saw they had high flow cats and i was wondering which do i have to order so it will work on my car.
97 GSR Reative Header/Apexi N1 Cat Back. The car is Obd2 so i would the need o2 sensor but i dont know if is in the front or rear of the cat.

here is a link
http://www.kteller.com/store/index.php/cPath/23_25

im guessing it is
Front O2 and a 2 bolt flange in and 3 bolt out flange on it? 2.5" piping? so that way it bolt right up to the downpipe off the header and the catback?

 

Sounds good to me.

Front O2---- is correct.

2 bolt in 3 bolt out flange--- correct again.

2.5 inch in and out....i know that its right for the Apex-i N1 but I have no experience with the Reactive header(actually never heard of!) but i'm pretty sure you won't run into any problems.

Can anyone else correct me?

 

i have that cat used for 200 miles. i sold my car so i don't need it anymore. let me know if u want it. 626 712-6575