My reg. is coming up i need to smog my car its a 99 ex, but it has a obd1 cat with a o2 welding in, i found a couple 50 state legal magnaflow cats. My question is which would be better the cat with the spot for the o2 sensor or get cat without and make a spot either before the cat or after (whichever is the right way) im going to buy one tomorrow so i need to know thanks in advance!

 

another question the first cat says C.A.R.B legal for california..
the second one for california says 50 state legal but not C.A.R.B
the one with the spot for the o2 sensor only says 50 state legal also.. do i need the one that says C.A.R.B, or just 50 state legal will be fine?

 

The last time I checked, the o2 sensors have to be in the stock location. You would need one before the cat in the lower part of the exhaust manifold and then the second one after the cat. As far as which cat to use, I would go with the one that says CARB legal on it.