Ok, I've got it now. On my 2002 there are two canisters up close to the engine block. They appear to be about 5" in diameter. These must be the "pre catalytic converters". Then there are two more more traditional looking units down underneath the vehicle on each side of the front drive shaft. These are the must be the "secondary catalytic converters". From reading the SLR information, the headers replace the manifold and pre cats back to the flange just in front of the secondary cats.

That seems like a reasonable setup to me. Whether or not it'll pass emissions is another question. I'd think it would pass fine, but can not be positive.

At $475 and ceramic coated, these headers are a good deal. The ones for my 3.4L V6 Tacoma were nearly $700 plus about $1000 to install them. I never did bite the bullet on those.

One thing someone with an ECM will want to look at...where does the air conditioner drain drip the condensation? If it will drip on these headers, that might be a problem. Several and by several I mean about 25% of the guys I knew who bought the Tacoma headers had them crack after the first year. Many believed this to be due to the a/c dripping on them. The whole "hot cold hot cold" thing. They always cracked right where the condesation would drip on them.

I'd love to get these headers. $475 is a good price. I think SLR needs to get CARB approved for this to be successful. Also, with them being stated as "off road use only" that probably means they also have NO WARRANTY. That's something else to explore AND get in writing should you decide to buy.

Who's up for being a guinea pig??