Hi there i am new to this but i been driving my 2006 cobalt for some time now its a 2.4 auto nuthing special but fixing it up and messing with it here and there iv added some up grades such as cold air intake fromk&n and a short header from protuneing lab , now i dont know were to look for a tuner i live in Chicago, also dont know if a plug and play piggy back system would work just as good as taking it to get a tune at a shop want to squeeze as much hp as i can and still pass emissions with those two modes please help thank you thanks from adrian

 

HP tuners.

 

For the 2.4 I don't know much but I remember looking into something awhile back called a vector tune?