allright guys heres the deal i have an 07 SS sc and my first mod was the gm performance exhaust. i put it on and almost imediately the engine light came on didnt notice a lack of power though. second mod K&N typhoon intake. felt like it ran good for the first day after i put it on. After that when i put the pedal to the floor the boost gage goes up past 15psi and starts to bog. i live in VA and went to richmond dragway. the best i could hit was a 15.9 sec qrtr ml. and stock it is 14.8 the last run it started bogging and the check engine light started flashing at me. So im a mechanic i figured to much air and exhaust not enough fuel right. today i had my stage two upgrade put on the car. Its slower than it was. the p0420 catalyist effecientcy below threshold bank 1 sensor 1. came on after i left the parking lot. but it will only come on at idle buts its weird because when i barely push the pedal it runs ok. when you put it to the floor now with stage two ill pull over 20 psi but the car isnt going anywhere. the dealer before i put the stage two on replaced the injectors and the o2 sensor that was supposed to be bad. they said it had a missfire code and i know these things are known to have leaky injectors. I came to the determination that 1 the dealer dont know shit, and 2 the leaky injector fried my cat. and it just seemed coincidental that it happened around the time i did my mods. im pissed i have the K&N cai, the gm performance exhaust and now my stage two and its bogging like hell. just curious if any of you guys had this problem with mods. or if the cats are known to go bad. i should be in the high 13's any of you guys with the same mods? what psi is it running at?