Any boost over about 12 or 13 lbs is going to be near 300 degrees air going into the intake. This is why an intercooler is desired to run more than 10 lbs of boost. The air gets heated up by the turbo intake fan beating the hell out of it to make more pressure. Cooling down the inlet air charge makes hp.
I'm going to throw in my two cents here and sorry if i step on anyone's toes as that is not my intent. I see either an incomplete or misconception of knowledge here that i'll explain with my theoretical and working practical knowledge of mechanics and engineering.
A turbo will increase the air inlet temperatures on these trucks for several reasons other than the 'turbine beating the hell of the air".
First, Yes icanfixall is right. A spinning object i.e. a fan blade, will increase the air temperature. This is due to something called fluid friction. As a fluid (air) is sucked through the intake, air filter, turbine blade, and interconnecting piping it will create friction. As a fluid moves across a solid object the molecules (air molecules) rub against solid molecules (others listed above) it is subject to friction. Also the molecules of air rubbing against one another. Some common practical examples are rubbing two sticks together to make fire, rubbing your hands together to warm them up, or rubbing your knees on the carpet to get rug burn. On a molecular level it happens the same way.
Second, and the most important is compression. Any time you compress a fluid or gas it creates heat. This is also due to fluid friction. You force the molecules together into a smaller area or volume to pressurize it. This is most important because it's not just the molecules rubbing against solid molecules as reason one above. ALL the molecules of air are now rubbing against each other as they are forced into a smaller area. Since we are talking about a diesel engine which works off compression of air and fuel, they both heat up until top dead center (or relatively close) until combustion happens at the sweet spot of temperature. Another prime example is air conditioning. When the AC compressor compresses the freon gas into a liquid, it heats up dramatically.
Third is the heat transfer that happens from other materials to the air. The turbine and casing is connected to the exhaust. Heat from the exhaust turbine will transfer through the common shaft to the inlet turbine. As well as the Casing around both. This heat transfer occurs before and after the inlet turbine wheel. Relatively cool air coming into the intake will heat up somewhat just before the inlet turbine which will further increase the compressed air as it exits the inlet turbine. A common example of this is placing an empty pot on the stove and turning the stove on. The hottest part will be at the bottom yes, but the top lip will also be warm and/or hot depending on the size of the pot.
Fourth and lastly is that CDR valve. The crank case depresure regulator valve will relieve excess pressure from the crank case. In design, any bypass exhaust gases that leak around the piston rings go to the crank case. CDR will relieve the pressure to the inlet turbine intake. The hot gasses as well as hot vapor oil released will also heat up the surrounding intake air BEFORE it hits the turbo. And again, the turbo compresses that and makes it even hotter. This is more prevalent when pushing the truck hard either flooring it or towing a heavy load. This is true at least for the banks sidewinder system that I have. I assume the same is true for the ats turbo, old banks systems, hypermax, and the later years of the ford's factory idi turbos. If i am wrong about the other systems I apologize but i openly admit i have no experience with the other systems.
Next is the intercooler.
I am going to post about volume because I know someone will argue the statements I'm about to make due to a common misconception of volume. If you remember back in your chemistry classes in high school or post high school, volume is measured at STP which stands for standard TEMPERATURE and PRESSURE. In lamens terms of my use of volume below, volume is the measurement of the number of molecules in a given area at STP. so if you increase the volume you will increase the number of molecules. Decreasing volume will decrease the number of molecules. Think of it as a difference in the number of molecules, NOT a difference in area.
Adding an intercooler works kind of backwards of what most people think. Colder air in the intake is not what actually increases the power of the engine. When you cool the air (assuming all other conditions are the same) the actual volume of air you push into the engine is the same. Colder oxygen does not burn/combust better than hotter air. However, this colder air reduces the heat inside the cylinder. By cooling the intake air you reduce the exhaust temperature. If you reduce the exhaust temperature you reduce the exhaust pressure. If you remember above that increasing pressure will increase temperature, the exact opposite is also true. If you increase temperature you will increase pressure. Therefore, if you decrease temperature, you decrease pressure. By decreasing pressure (i.e. exhaust back pressure) then you have now allowed the engine to breath easier. The pistons no longer have to waste as much energy/power to force the exhaust gasses out. You still push the same volume of air the only difference is the pressure working against the pistons. This is also true by increasing the size of your exhaust pipe. An example of this is taking a pop bottle and filling it full of hot air by setting it in the sun with the cap screwed on lightly to release pressure. Then take that same bottle after a couple hours and seal the lid. Stick the bottle in the refrigerator. After a couple hours of being in the fridge the sides of the bottle will actually suck in. The amount of air molecules in the bottle is exactly the same (assuming the cap didn't leak) all you did is lower the temperature which lowered the pressure (or in this case you created negative pressure or vacuum).
The other dynamic that comes into play is the pressure drop across the intercooler. Because you are now cooling down the air, there will be a difference in pressures. The outlet pressure of your inlet turbine may max at 10 psi (This is using the example of my banks sidewinder turbo) but by cooling the air through the intercooler (note the drop in temperature drops pressure stated above) the actual inlet of the engine will be a lower pressure by a few psi. The difference in pressure depends on the size of the intercooler for two reasons. One is size because of the amount of area inside the intercooler. The larger area of air of the intercooler will take more air to fill. Second is the size due to cooling. A larger intercooler will cool the air more. The smaller the intercooler will see a one or two psi drop. A large intercooler may see a three or four psi drop. The turbo may read 10 psi, but the engine inlet psi may be between 6 and 9 psi. This is important because the pressure line for activating the wastegate (banks sidewinder) is ten psi and it senses it in the OUTLET of the INTAKE TURBINE. Now that you have made the entire system more efficient, you can adjust the wastegate to actuate higher to raise the actual engine inlet back to 10 psi (or whatever psi you are comfortable with). By raising the wastegate actuating pressure you will need to raise the inlet turbine pressure to 11 to 14 psi due to the 1 to 4 psi drop.
The last note of the affects of an intercooler is that by decreasing exhaust back pressure the air now moves more freely through the exhaust. This will actually increase the movement of the turbo. Remember that by all else being the same, you are pushing the exact same volume of air through the engine (unless you adjust the wastegate to raise pressure, then you push more air). But by allowing the air to move more freely by reducing the exhaust back pressure, the air moves faster which will therefore speed up the turbo. I noted this last because it is fairly irrelevant/negligent compared to the other two reasons above.
I hope this post helps everyone understand the actual changes to the engine with reguards to turbos, wastegate, and intercoolers.
biggest thing for me will be plumbing on top of the engine. My intake setup I built is right in the way of the intake hat. Good thing I have an aluminum welder 
