I have a 05 cobalt ss/sc I've got typhoon intake SRS exhaust . I have simens headers and 80lb injectors coming in the mail. What size pulley would be safe and is it absolutely necessary to get a new PCM? I've got over 12 grand in repairs and I don't wanna blow this up lol

 

You won't need a whole new PCM you can just get yours tuned. You could go 2.9 or 2.8 but I know ZZP recommends a downpipe too at that point. Pretty much that same set up i'll have in a couple weeks

 

80's?
Buy a 2.7"

 

Forgot to mention you should look into a heat exchanger and maybe dual pass and option b

 

Thank you