2003 Nissan 350z Base Model
167K miles. Daily Driven.
Codes: P0327, P0328, P0430.
327 is for Knock Sensor 1 Circuit Low Input (Bank 1).
328 is for Knock Sensor 1 Circuit High Input (Bank 1).
430 is Catalyst System Efficiency Below Threshold Bank 2.
I got these codes several months back (except 430) and replaced the Knock Sensor, both Cats, and both O2 sensors. The only mod I have is an after-market Cat-back exhaust. Basically, my after-market cats are not as good as the factory one (based on some Google research prior to this). I do not feel, hear or see any performance issues in regards of acceleration, MPG, etc.
Is there anything I need to worry about?

 

Did you clear the codes before installing the new parts? If you did and still got these codes, after replacing everything, then that means the sensors weren't the problem. Make sure your connector for the knock sensor is not damaged and sending the proper voltage.

As for the p0430 code, did you replace with a brand new cat? That code tells me your cat is possibly either clogged, worn out, or broken down inside, thus not reducing emissions as it should to a standard.

 

Did you replace the knock sensor sub harness as well? Always replace the sub harness with the sensors. The 430 code is just the aftermarket cat. Nissans don't like non-OEM cats. Google "O2 sensor J-tubes" and get a set.