[2K3_Boxster_S]

recently installed Headers w/Cats, bypass midpips and high flow muffler. I noticed the car no longer cuts fuel or hits rev limit at 6800 like before.

I have been carefull not to go anywhere near past 7000 rpm. I am getting a CEL for the rear O2''s reading the same as the front's P0420, but cant see how it would be relevant.

I don't want to take it any higher to find out if it indeed may still be working at a higher RPM as I am on the stock IMS. Any ideas of whats going on? Thanks.