Originally Posted by 4RunnerAquasport

That is an accurate description. Your Catalytic converters on the V8 are attached to the factory exhaust header/manifold. So when you remove them they come out together. See: Manifold/CC pic
I actually still have these, nothing wrong with them.

I ran just the Thorley Y with the factory manifolds and an old Thrush muffler for a year and 1/2. Sounded pretty good.

Now for the o2 sensor placement. The first two in the upstream flow are NOT o2 sensors. They look almost identical, but they are air/fuel ratio sensors.
If you look at the pic of mine, you'll see a small hole on the inside of the bend. Thats where the A/F sensors live. If you go with just the Y pipe and do not replace the factory manifolds, you will not need to touch them.

Behind the catalytic converter in the down stream flow are the o2 sensors. They live in the Y pipe, and will then live in your Thorley Y pipe.

Originally Posted by 2003V8LTD

I agree, except that the offset of the TRD Pro wheels is 4mm instead of the stock 20. Having the wheels 16mm outboard of where they should be, on each side, messes with the steering and suspension geometry. No way would I ever do that.

Originally Posted by importman

Not at all. Just do a search on eBay. I don't have a link handy. I can't remember exactly how much it was but it was cheaper than I expected. Like between $100 and $150 if I recall. They are aftermarket units but they look great and work just fine. You just have to find your paint code and order one with that code.