The CC & O2 were stolen last night on my Tacoma in Phoenix, AZ. It was cut about 4" from the rear of the CC. All wires on O2 after plastic cut on the front. The crossover connection cut in the rear flange. So... reading here that aftermarket part for CC is not recommended (which is what my jap auto mech confirmed). BUT, 4 more 'muffler shops' tell me both a Universal CC & O2 which is rated OE, is okay. Both shops will build the bung & rework pipe--of course they do the work. Price by my jap mechanic is $1300, and price by 'muffler shop' is $500.00.

Q: Will the check engine light come on sporatically later-on if the parts are Aftermarket rated OE & not factory OE?
Q2. Does my jap mechanic have more insight on why using the factory part over the Or more importantly will the 'general muffler shop' be okay?
Q: Is building the O2 pipe or bung a big issue?

What I am hearing from previous posts about CC & O2 are great. And... should my general concern be welds leaking? Or the fabrication? So many questions. Check Engine light, and just the shear difference in replacement cost quotes (Sorry, I'm not replacing myself, I must determine if I get it done at a muffler shop or by my jap mechanic who works on my 3.4L 4X4 manual trans Tacoma)... PS I also understand the replacement of a CC or the 02 was about ready -122,000miles.

NOTE: Quote from GOV-Common Sense///
Vehicle performance can also be affected by
the use of the wrong converter and, in some
severe cases, converter or engine overheating
could occur, resulting in unsafe operation and possibly
engine damage.
Because of the effects of backpressure and heat
created during operation and the effectiveness
and compatibility of some emission systems with
certain converters, it is important to make sure
that the converter installed is the proper one for
a customer's car or truck. An original equipment
converter is designed as an integral part of the
vehicle's emission and engine system to achieve
the lowest possible emissions and optimal performance.

I would go with a factory O2 sensor. They don't cost much more then generic.

When my cat went out, I replaced it with a generic bolt on model, then took it to get smogged. The truck just passed. When it came to get it smogged a few years later, it not only did not pass, but was a gross polluter. So I spent the $700 for the OEM cat and got it re-smogged. It not only passed, but had lower number then when it was new. One number was 0. (I forget what one) The smog guy had to check twice to make sure I was not pulling something.

I don't know at what year Toyota went with two O2 sensors. One before and after the CC. If you only have one before the CC, then the CC matters little since the ECU can't measure it.

If you have one after, then you will be taking a risk with a generic model. If/when it goes bad in a few years, you will be replacing it again to get the check engine light to go off.

Thanks for the advise. Sound advice. Appreciate it. Off to work it out now.