Type R Club of America

I’m currently working on putting my 98 ITR back to carb legal. So I can drive it on the street and not just track it.
My engine as is now
B18C5- CTR pistons
Ported head
Skunk 2 stage 2 tuner cams
Aem fuel Rail and pressure regulator
550cc injectors
After market TRi-y header
Skunk 3 inch Mega RR header back exhaust
So I still want to make as much power as possible but be able to street it and not have to worry since Im in California.
What’s the best carb legal header still available? Also to pass smog do I need oem injectors or just the same size injectors as oem. What parts can I keep and get bye and what do I need to convert back to? Like my cams . I know stage 1 are carb legal. has any passed on stage 2 cams?

You can find a lot of answers to your questions here.

I like my Comptech Headers. Took me a while to find a good set. If you want to see a full set of CARB-legal, check the CARB database here. There is no good way to sort by vehicle, but if you load the exhaust section you can CTRL+F and search "integra type r" to see all applicable. Make sure the EO is not superseded, and that the headers come with a sticker or stamp referencing the latest valid CARB EO# to make smog easy.

Looks like your exhaustive list is...

Edelbrock TES/TES Shorty
Holley Airmass
Biggs Airmass
DC Sports/DMM Motorsports Header
Comptech/CT Engineering

Of these, I'm only familiar with Comptech and they're usually well-regarded in the ITR community. As far as "what's best" - you're probably looking at marginal differences. You will need to abandon any hope of putting down any significant power increases while being completely 100% smog legal. Will you notice a 10hp difference depending on what parts you choose to install? I guess that's up to you.

Your Injectors and FPR WOULD need swapping out with stock to be legal, but it depends on A) your smog tech's willingness to overlook on visual check and B) your actual emissions coming out the tailpipe. Many people get by with FPRs, but it depends on your tech.

Technically, any aftermarket cams need to have exactly the same grind as OEM to be legal (this EXCLUDES stage 1). But no tech is going to take off your valve cover to inspect. What matters to them on this is what is coming out your tailpipe. Aftermarket grinds can affect this. Have a precheck done or hook up to a sniffer that is not part of smog to see if you'll pass.

Your exhaust will need a CARB legal Catalytic converter -this post details how to find them. A weld-in to your existing system should be fine but it will of course restrict your flow down quite a bit - so you might choose to go with a smaller or stock system anyways.