Check Engine Light.....?

[GundamWZero]

Alright... have the car for less than 3 weeks and I get a check engine light this morning. So yeah... I am ready to skin a dealer. However the car ran perfectly, no loss in it's powerband and the fuel economy haven't diminished.

Now being mechanically inclined, currently own a fleet of Nissans (Altima and Armada, respectively), and maintained a 86 Nissan Maxima until 2003, I have some knowledge on how these bulletproof engines can get pretty temperamental when it comes to intake, exhaust, and the sensors that manage them. So I am thinking that the culprit has to be the oxygen sensor at the exhaust manifold... maybe near the catalytic converter, for the car has an aftermarket exhaust installed.

However, since this is my first sports car, I could be wrong. So I am checking to see if anyone here had caught a check engine light after running an aftermarket exhaust system after a while of running an aftermarket exhaust with drop in performance filters.