in CA, tp is illegal. hfc is legal.

youtube has clips of hfc on stock exhaust. that's what i run and love it.

 

I don't have the balls to run one here in CA!

 

Actually HFC are not known to be legal in the state of California anymore. Sure emissions is the same as a cat but CA does no recognize them.

 

So if you replace a defective cat with a different brand cat than factory, are you hosed? What would the difference between a 3rd party regular cat and a high flow cat be in the state's eyes? How would they tell the difference just looking at the casing?

 

It's not illegal unless your county has emissions.

 

A new law is passed you can read it up on Magnaflows website; I am not certain when it will come into effect exactly here in California. The law is if a cat is defective one will need to prove it is truly defective. For example a technician will examine it and say "yes it is defective etc" then he will fill out some paper work. There you can obtain a OEM replacement cat or an aftermarket replacement cat. Note not a HFC! From there you will have to carry some sort of paper work that says you had the cat replaced due to a faulty stock cat.