Catbacks, AOS, and intercoolers don't require EOs so those are legal (noise restrictions on the catback is a separate issue). Parts that have gone through the CARB evaluation and have been granted an exemption are legal. Parts that have an exemption and will give you a moderate power gain are generally exclusive of each other. You can search for EOs on parts
here. The whole thing is moot since you'd need a tune (illegal) to see the power gains.
The real question is, what mods can you make, get some power, and still pass smog without swapping parts? Quite a bit, actually.