i want to get headers on my 93. i am pretty sure i will be getting the MAC midlengths with the included y-pipe. i was wondering if anybody knows where the 02 sensor is on 93's, becuase i looked on the cat and stuff, but didnt relly see anything and i havent given it a real good look yet, becuase it was only sitting in the street so i couldnt get under it much. also there are MAC headers specifcially for 93's because the EGR is above numebr 8 and AIR is above number one, so these headers should basically bolt right up and the fittings should work correct? lastly, i want to put a pipe in place of my cat for regular driving but then put the cat back on when i go to emmisions. there is only a 2 bolt flange from the y-pipe to the cat, correct? would i be able to bolt on a regular 3" pipe to the collector, becuase its that size. and also if i had the stock cat, for emmisions would it be able to bolt onto the 3 inch collector? thanks alot

 

There are 2 O2 sensors.

The driver's side one is pretty high up. Its in the driver's side manifold.

The passenger one I think is also in the manifold or just below it.