My 2003 LS430 with ~115k miles needs cats. The Toyota/Lexus option is crazy expensive. Has anyone had any good or bad with the much more affordable ebay cats? example: https://www.ebay.com/itm/12427855835...kAAOSwWmdfIeQ4

I've already replaced the Y pipe part of the exhaust after having a leak at the union.

 

Don't think you can expect much for that price, good if you plan on selling the car shortly. What about BRE?
https://www.rockauto.com/en/catalog/...converter,5808

Another option but still $$$$$
https://www.amayama.com/en/part/toyota/1845050350

 

Needs cats due to P0420 or rust/leaks? I'm also curious on said ebay cats...

 

The CATs should be a lifetime item and are made from stainless steel so should never rust.
They go brown from heat cycling, but that is not rust.
Why do you think you need to replace them?

You need to make certain that your new Y-pipe is sealing correctly when mating with the CAT as any leak there will cause the O2 sensor code.
If it's due to the O2 sensor codes, have you replaced the downstream O2 sensors? I'd do that before messing with the CAT itself.

I'm currently at 131k miles and still on the original CATs.

 

Thanks for the responses. I have P0420 and P0430. I do agree that it is very odd to have a cat go bad with relatively low miles. Is there a value to check through OBD to see if the secondary o2 sensors are just reading strangely?

 

If you have 420 & 430 then that is both sides of the exhaust. Odd that they would both go at the same time.
More likely that they damaged the O2 sensors when they fitted the new Y-pipe, or that the new Y-pipe is not sealing to the CATs.

 

thanks @BigBoomer .
That does make a lot more sense than 2 cats going bad. I'll get it in the air this weekend and see what I can find