New Fabspeed exhaust system for 2002 Boxster

[Dramas]

Hello, I just recently installed a new Fabspeed muffler exhaust system that came with resonators replacing the second catalitic converters, the system connects all the way to the headers. I kept the OEM headers with cats since these have the O2 sensors connected to it. The 2002 Boxster drove well for about 70 miles and the power is noticable the sound was loud and amazing I love it. At one point at speeds of 40mph the check engine light came on but no change in vehicle performance noted. I immediately called Fabspeed to get input since they advertise NO CEL for these mods and that they comply with warranty and 50 state emissions (reason why I bought it). Fabspeed said that this exhaust system should not have any ill effects whatsoever on the CEL since the O2 sensors are on the first cats and the second cats are delletable with no problems (seen on their website video). Fabspeed advised that I should check my cat O2 sensors and MAF since I am currently using a K&N filter on it. I disconnected the battery when I started to work on the car and noticed that the CEL disappeared (may have reset) after I recconected the battery. Anyway I still went on to check my O2 sensors and cleaned the MAF with CRC MAF cleaner to make sure that everything is in order before I restarted my car. The CEL has not come back on at this time, I am getting a Durametric system shipped today to check what really happened. Then I will test drive the car. I need your expertice and experience on this. Is this exhaust really emissions compliant? Does it have an effect in the CEL? Does replacing the 2nd cats with resonators (part of the whole Fabspeed system) have ill effects after all? I live in California and I have upgraded several cars but always kept them street legal (don't like headaches). I really liked the Fabspeed exhaust system it looks, feels and sounds great, but I also like a good working car. Please share your thoughts and experience on this matter, Thank You!!