I just replaced my front O2 sensor yesterday and I have stock twins. It wasn't that hard and it took me about 35 minutes and if I had to do it again I could do it in 15-20 minutes. You have to do it from under the car. The front 02 sensor is on the exhaust right before the downpipe starts. I just got my car on jack stands, removed the small support bracket(I think that is what it is called....it has four screws and I had to remove it to get my hand up there to install the downpipe and the O2 sensor), and then from there you can just reach up there and take out the 2 O2 screws with a 12mm socket and put in the new one.
After that you have to go in from the hood and follow the O2 wire to the connector, which is right by the radiator fan and remove and replace. I don't have any pictures but I hope I helped you somewhat.
www.eastcoastsupraz.com
After that you have to go in from the hood and follow the O2 wire to the connector, which is right by the radiator fan and remove and replace. I don't have any pictures but I hope I helped you somewhat.
www.eastcoastsupraz.com