Hello all, I have a question. I have a Isuzu NPS300 and am towing a loaded car trailer behind. I am looking at changing my standard exhaust to a 4inch exhaust to increase my power and also concidering getting a chip installed as well if required. I am having a problem aquiring a 4inch exhaust brake to suit. Is there anyone out there who has done this modification successfully that could guide me as to where I can purchase one? Has anyone installed a chip as well, if so on both, how much has your performance changed? Many thanks
