Is this a too good to be true deal?

[legobumb]

I know the general stigma against buying aftermarket stuff on ebay or amazon, but I'm not willing to spend $600+ on a new catalytic converter for my 2002 325xi. Especially since it's got 2 years before I can just delete them (tri-state area of New England). Today I finally got around to trying to change out my downstream oxygen sensors, but one of them was completely seized and took the threading with it out of the catalytic converter, thereby rendering the entire thing useless now. My state requires emissions testing (CT) and obviously won't pass without both of the oxygen sensors actually doing their thing. The old oxygen sensor's integrated heater kicked the bucket and started throwing an intermittent code until finally it was a persistent code this past month.

I've been looking around on classifieds on here and even posted a WTB ad for a secondhand cat, but then I found this ebay ad - $300 for a pair of new cats, front and rear, with all of the nuts and bolts and gaskets required for installation. I think that's a really good deal, but is it TOO good? It says it's "for vehicles with California emissions system" which I've no idea what that even means since I don't live there. I know they have pretty strict emissions testing rules, but that's the extent of my knowledge of that haha. However when I scrolled further down, I noticed the ad then says it's only 47 state legal and cannot be sold or shipped to CA, ME, or NY. Which to me, kind of contradicts the whole "for vehicles with California emisions system" statement lol. But again, I know nothing about CA emissions requirements.

Below is the link to the ebay ad I found. If it's too shady then I'll just forego it and continue my efforts to find a secondhand one from someone. Any advice or insight would be greatly appreciated.

Link

[randy72877]

Get an M18x1.5 thread chaser and a new o2 sensor.

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[legobumb]

Get an M18x1.5 thread chaser and a new o2 sensor.

I've already tried tapping the hole. Sorry I didn't mention that in the original post.

[MarcoZandrini]

California emissions standards were adopted by several states.

[legobumb]

Okay so this is actually a good deal, then? I haven't found anything better elsewhere for *new* cats. RockAuto has bank 1 cats in the $200 range, but if I can get bank 1 AND bank 2 for less than $100 more (hardware included), then I'd be silly to not do that if I go the way of new ones. So far I haven't had much luck in finding someone with a bank 1 cat laying around for my car, which means I might have to bite the bullet on buying new ones. Realistically, I only need them to last at least the next 2 years until my car is 20 years old where it becomes exempt from emissions testing.

[randy72877]

If you can't weld, take it to an exhaust shop and have them weld in a new bung for the o2 sensor. Weld in bungs are available online dirt cheap. Aftermarket cats don't last long and should be avoided if possible. It's common for them to last about a year and then you will get catalytic converter efficiency codes (p0420 and or p0430)

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[legobumb]

I didn't know that was a thing. I'll certainly look into that and get back with an update

[Jackson42]

The CA-legal replacement cats differ only in that that they've been certified by the California Air Resources Board (CARB) and have a special number on them as a result. They also run 25-50% more expensive as a result. There are downsides to having clean air here in CA - all economic - and this is one of them. our Spidey sense that this is too good to be true is probably right - I can't see any way even a single CA-legal cat could be sold at a profit for $300, much less a pair. Regarding the stripped O2 sensor, it has the same thread as a spark plug, and Helicoil kits are available to replace stripped spark plug threads. You might consider going that route.

[spyderg0d]

I would just have a new bung welded in. It will probably cost a penny if they have to remove the cats to work on them..
I boaght canadian spec converters and had them shipped to ny.. Technically its illegal on thier part to ship them to me, bit i dont think ny can prosecute a canadian based business.. Its not illegal to install converters that are not CA passed standard. Its also not illegal to have non CA certified cats that preform properly on a non modified emissions system.. Its only illegal to sell non certified cats to customera expecting them to pass the other atates guidelines.. So... My canadian spec $300 converters passed NY smog and inspection with no problems. Because realistically, a cat is just a cat and they all have the same standards if the emissions control is the same and checks functionality the same.

[Mless5]

If you can't weld, take it to an exhaust shop and have them weld in a new bung for the o2 sensor. Weld in bungs are available online dirt cheap. Aftermarket cats don't last long and should be avoided if possible. It's common for them to last about a year and then you will get catalytic converter efficiency codes (p0420 and or p0430)

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After that, if it still isn't doing its job you thread in spark plug spacers to further space out o2 sensor and you are all set.

[legobumb]

Thanks for the information guys. I've already called a custom exhaust shop and explained what I needed to have done and they're looking into it and gonna give me a call back.