Need help

[ananmech]

i have TA 2001 and i have installed pacesetter headers and y-pipe and magnaflow cat back (without tunning) after that i have weird noise it's like steel hitting steel and i a low RPM it shake a lot plus the rpm drops below 500 rpm and it just doesn't feel comfortable as before please :wtf plus i have the CES light is on now they told me to change the 4 O2s sensor. because the pacesetter header comes with only 2 i had to drill into the y-pipe to fit the other 2 O2s

The modes are :
pacesetter LT painted with pacesetter Y-pipe , Magnaflow CAT back and K&N filter MSD wires
should I go for diablo tuner?

[Y2KPewterSS]

http://www.thunderracing.com/catalog...&vid=3&pcid=54

Part # 95-LS1-HR