Someone had told me that if I add a cold air intake to my truck I'm going to have issues, as in something break, because I have high mileage on it (190,000 to be more exact) he said I'd have to change some internals is this true? And if so what internals am I going to have to change?? Also if I wanted to change my headers would I still need to change out some internals?
That someone is a know nothing idiot.
You are not going to suddenly load up your engine with a CAI. Yes you have over achieved with your 4.7 but if its taken care of a little more air shouldn't cause any problems and there is nothing that will stop working. If anything, the engine will breath better and you may find a tick or two worth in faster throttle response (or not). On a 2002 4.7 you'll remove the OEM air hat which is a big air flow restriction because Dodge was trying to reduce under hood throttle noise with that design.
Two primary CAI types, open top CAI which are loud in a bad way (poser) giving a lot of throttle noise under the hood, and they really don't bring cold, denser air for combustion because they are heat saturated by virtue of sucking air from under the hood (K&N, AIRAID, etc).
The second type are closed CAI that suck from outside the vehicle usually using the OEM port in the right fender well or with additional ports. I don't know if S&B or Volant make a model for the '02. Also in this group is the Vararam which is semi-forced air for the Gen 4 Rams, but I don't know about availability or fitment for the '02.
For headers the thing to determine is if your replacement piping will displace any factory O2 sensors. If so the new piping needs to include ports to put the O2 sensors in. I don't remember where on the Magnum 4.7 that Dodge put the O2 sensors, but I do not recall them being in the factory header; I seem to recall they are down stream after the header joins with the piping to the catalytic converter. Short tube headers probably wont impact your O2's, whereas with long tube headers you may (may not will) have to address the location of you O2 sensors. A responsible vendor will already know and stock or order the right type of tubes for you.
A word of caution, headers may generate additional horsepower (short tubes not too much worry, but think a bit before going with long tubes) that could change cylinder firing temps, exhaust valve seat wear, apply extra torque on your crank shaft and increased loading on your bearings.
That's where that high mileage should be considered.
