I'm thinking I will get my exhaust system done and get the car a tune, but I don't know what is best between 4-2-1 with 2.25" or 4-1 with 2.5". What set up will get the most power out of the d16y8 engine, I know it not a big gains that why it's better to do the one that will gain the most out of the 2 setups. (I have Injen CAI)