Usually if the P7100 isn't timed properly you will notice a loss of hp and poor fuel mileage. When i say poor it is 14-15 range instead of 18-19 range. But in your case the fuel mileage will be mostly affected by that huge air dam sitting on top so the fuel mileage may not be an accurate measure of performance. My truck once had a set of large tool boxes and a ladder rack that extended up above the cab and i lost about 2 mpg because of the wind drag. I know a couple of local guys that still have 94-97 12v trucks with torque plates, air filters, turbo vacuum 90s and they are getting 30+ lbs of boost and 19 mpg. On average a diesel makes 10hp for every lb of boost. My 97 has a 5speed. Making these few changes made a HUGE difference in towing because of the increase in hp. 5 speed trucks, 3rd and 4th are too far apart. When pulling hills 4th was too tall and downshifting to 3rd was too low. After the mods you could leave it in 4th and just power right up the inclines. Filter, torque plate and 90 is less than 500$. The gauges are only needed to watch your egt's and I would recommend one for transmission temp if you have an auto. A new intake tube will make a slight difference as well, 130$ from CXracing on eBay. I am out of town right now but if you would like pics I can forward some to you when I get back.