Ok here is the situation. I replaced my whole exhaust system( Warpspeed fed-spec Y pipe, stock cat and warpspeed 2.5 inch b pipe and rear section. My cat converter is bad. I live in California but moved from seattle where I bought my car thus, my car is a fed-spec maxima. When I entered Cali and did a smog check to get registered I passed with stock fed-spec cat. In january i will nedd to pass emissions again here in cali. Should I buy a fed-spec high-flow cat or get a an OBDII cat that is specially made for cali's high emission standards? The OBDII are roughly about $250-$300. High flow regular cat about $100. Remember I passed with fed spec a year and a half ago. I'm so confused.
Gramdacious

 

It seems you're very confused. You car is OBD2 and I can't see what that has to do with your cat converter. The cats are the same on cali and spec from what I saw. I didn't even know they made a thing like a OBD2 cat, seems like a scam to me. Also, I'm not sure that buying a high-flow cat is a good idea emissions wise. They aren't as good at doing what they are meant to do. There is a reason why the stock cat is in the $700+ price range.

 

The stock Y pipe is also in the $800 range, that doesn't mean that it is 4 times better than an aftermarket Y. I was a manager at a nissan dealership and I have seen first hand the raping and pillaging that the manufacturer and the dealerships can impose on the general public. As far as the OBDII cat, I was shown one at a reputable muffler shop and I compared it to my cat and they are definately different internally. I really didn't see how a "high flow" cat would flow that much better than a stock cat because the stock cat has the same inlet and outlet size, and the interior seemed very wide, wide enough to flow whaterver the inlet would allow. But if a "high flow" cat can pass emissions then I'll go with that due to the price difference.

 

The stock cat is good enough.
You will not even get .5 hp more out of a high flow cat.
There are no differences between the Cali and Fed spec as far as the cat is concerned.
There is, however, a difference in the type of y-pipe between the two.

Save your money....keep the stock cat....or if you must get a new one....get the cheapest one possible that looks like it is made decent.

 

True, but the stock y-pipe has two CATs in it doesn't it? The honey comb in the OEM cat is much more effective than the aftermarket ones.