Replacing your tips is a safe bet – anything else can get complicated.
“The sale and installation of an aftermarket exhaust system remains legal in California so long as it does not exceed a sound level of 95-decibels when tested under SAE J1492 and complies with all other exhaust and safety laws and regulations. Now, a motorist cited for violating the current California exhaust noise law may receive an immediate fine. Previously, motorists received what is known as a “fix-it” ticket, which allowed for 30-days to correct the violation.” Source: SEMA
Modifications with a CARB EO number / sticker are considered approved by CARB and will pass a smog check. These modifications most often do not tamper with any emissions related devices or perform similarly to the OEM catalytic converters.
“Aftermarket catalytic converters must be exempted from California’s anti-tampering laws in order to be legally sold and installed in the state. If an aftermarket catalytic converter is shown to be durable and meets vehicle emission control requirements, it is granted an exemption Executive Order (EO) that allows it to be installed on specific emission controlled vehicles.” Source: California Air Resources Board
Legally, you will not be able to delete your catalytic converters on a vehicle designed for road use.