Outlaw, for the cars before 1996 only have 1 O2 sensor, so it would ber from the cat-back. For your car which is after 1996 (OBD2) you would need to do it either after the second cat or after the second O2 sensor. After the second O2 sensor removes the second cat which is ok. You can not get rid of the second O2 sensor. Now what you can have them do is do it from the flexible pipe right after the first cat (assuming you have the cat on the exhaust manifold) and have them add a bung for the 2nd O2 sensor which is what I would do. Mineke and guys like that will charge you a fortune and won't remove your second cat due to Federal laws. But a local hole in the wall exhaust shop should be abl;e to do it for a decent price. Just look in your phone book for exhaust. The price for me to do a cat back on my 2001 elantra would cost me $110 for the press bent aluminum piping and install of the pipe and aftermarket muffler. FYI: pre-1996 cars have OBD1 which only have 1 O2 sensor. 1996+ have OBD2 which has 2 O2 sensors. And if you car is Cali emmisions it will have 2 cats. The second cat is ok to remove there is no way to monitor for that. And in order to prevent the CEL coming on without any cat or with a high flow cat somtimes you would need what is called and O2 simulator. Avail from http://www.casperselectronics.com/cgi-loca...product=IMPORTS. Summit racing also sells them the part number is CEL-104037.