Does Nissan offer a catback exhaust and cold air intake that won't void my warranty? Maybe through Nismo.

 

No unfortubately there are no Nismo performance parts for our cars.

A cat back is only going to void the part of the warranty pertaining to the exhaust, nothing more. If your engine did get injured Nissan would have to prove that your cat back caused the damage. Highly unprobable in this case.

Same thing for the intake.