best thing you can do for it is get the hypertech unit if you want to "tune" it. There is no way to reconfig the stock ecu w/o a standalone unit and for basic bolt ons its not worth it, so a plug and play hypertech unit is your best option

Oh yeah i forgot to mention i also have the advanced timing mod done

 

Hmmm. I see a lot of different things on here. I have a 04 2.0 with an obx header and complete custom catback with absolutely no resonators at all and a glasspack with 2.5in piping. I have a video on it with youtube i will have to put it on here soon. I agree. 4-1 design with with obx header looses a tad low end but when the vvt kicks in with the combination of the header i feel that the pull and the high end gains are much stronger than stock.

Lots of people would state having that little of restriction would lose a ton of back pressure and low end power which is true, however, I have a dual exhaust design that awkwardly enough one side pushes exhaust out while the other side actually creates a vacuum type effect "creating" the back pressure that I lost. There is no science I can tell you in these tests but having my friend in the car and revving the car up and I back at the exhaust. He noticed that up until about 4k rpm the one side of exhaust "sucks" in air. Once he got over that 4k mark i notice that there was full blow exhaust coming out of both sides. To me this make sense our tq curve taps out around 4K-4.5k. At that point you are no longer using the low end tq and things that accompany low end tq on the exhaust side like back pressure, to pull you out of the hole. At the point you are using your straight highend HP to pull you out and keep you going.