Gauges are a must have, even on totally stock trucks. The EGT (exhaust gas temperature) can be very high and over the max limit when towing your camper. On a hot day, the stock intercooler (charge air cooler) is very limited. It also is behind the AC condenser and on a hot day most people have the AC on. Hotter the air into the engine, the hotter the gases out of the engine. Some say that the manufacturer design limits to protect the stock engine. If this was really true, where is the sensor in the exhaust system to measure this limit. Only the new 07 models have sensors in the exhaust system and that is for other reasons. Now add the effect of a dirty air cleaner, heavy, at design or over loaded truck, above sea level, bugs and road dirt blocking air flow, etc. Without gauges, you are flight by the seat of your pants. Good Luck