i think guys alway recommend a clean mass air flow sensor. if it is dirty it could be giving the wrong info to the computer. As far as only a adjustable fuel regulator yes that will help but say you are running lean and adding fuel pressure doesn't cut it. You may have to upgrade injectors or even fuel rails. I'm not sure in your application if that is even neccesory but i think there is more to tuning the a/f ratio on a efi car then just switching the fuel pressure to the injectors.
See with us carb guys in order to tune air fuel ratio we are changing jetting of carbs adjusting fuel pressure adjusting float bowl lvls changing power valves and switching accelorator pumps. i doubt tuning a fuel injected car would be easier then a carbed one. so i would say go to innovatives web site and look up in there tech section how to tune EFI with there product.