Exhaust Manifold Replacement - OEM or URD

So my exhaust manifold has been leaking and I'm finally tired of the noise and wanting to replace them. I understand this is a common problem for the Tacoma so I guess my question is, should I replace the exhaust manifolds with OEM (only to have the problem reappear) or maybe go with an aftermarket one like the URD?

I know with aftermarket one I'd lose the first set of cats, but not that concerned. What's everyone's thoughts?

2006 Double Cab, TRD Off Road, 4x4, AT

 

Is the leak coming from a crack in the manifold, where it bolts to the head, further down?

If you’re planning to do the work yourself, I’d start a regiment of getting the fasteners soaked with a good penetrant like liquid wrench, pb blaster, kroil, candle wax… Exhaust fasteners are notorious for rounding off or breaking.

 

4.0? Does URD even have that?

headers will add sound
one concern may be future resale and smog-ability

I hear 05-11 is more friendly to exhaust work. Having secondary O2s before post cat allowing for catless Ypipe. There may be no difference with headers though.

not sure if all the header companies are basically the same, or if there’s any clear cut best winner. Itll probably cost more than a decent shape used one.

some headers come with a different flange that could need custom work at an exhaust shop to mate up as well.

first time I’m hearing of a leak. Mine isn’t. What part is leaking? Are they rusted?
If it’s a crack, welding might patch it. Or even JBweld.

depends on what they’re made of. Steel is usually better. Iron ones can rust quicker.

the first set of cats is important to not throw a CEL. Some headers may delete it while some may have built in cats. That hopefully filter well enough to not throw a CEL. Depends on where you live I guess.
And if it is legal, If the CEL can be coded out or something to not have it still lit up constantly.

 

This is the aftermarket one I'm referrng to:

URD Spec-U LT Headers for 1GR-FE, Tacoma, 4Runner, FJ Cruiser - Underdog Racing Development (urdusa.com)

I'm not sure where the leak is coming from TBH - but I know for sure it's leaking from there. I've can hear it coming from the manifold. I checked the rest of the exhaust and there's no leak but can't really get up in the manifold area (I mean, I can, but since it's hotter and harder to reach, I haven't thoroughly checked).

From what I've read on the forums, it does seem to be common.

 

Problem is with that header, you need an o2 simulator and URD no longer makes them.

 

$106 GTC ST05 Oxygen Sensor Tester and Simulator by General Technologies Corp

https://www.amazon.com/General-Technologies-Corp-ST05-Simulator/dp/B001TCWLO6

I was thinking this might work as a substitute but it looks like no. Their partial description:

• Two buttons allows for simulation of rich or lean conditions to monitor response of the engine control module.

 

You should be able to see traces of carbon leaching from the leak. Try a dental mirror and flashlight.

$16 Ullman Devices HTB-2T Oval Pocket Telescoping Inspection Mirror, 1" x 2" Mirror, 5-5/26" to 28-1/4" Handle

https://www.amazon.com/Ullman-Devices-HTB-2T-Telescoping-Inspection/dp/B008Z67HPM