If you have the stock lift pump, you need to upgrade to something a little better, F.A.S.S., AirDog, Raptor, etc., to protect your Injection Pump You need to be above 14 psi at idle, and try to keep it above 10 psi at WOT. When was the last time you changed your fuel filter, as this may be keeping your fuel pressure low.
For the EGT, the best temp to keep it under is 1250*, much hotter is when you start to melt aluminum. But, you can go past this number for short bursts, less than 30 seconds.
There should not be a cat on your truck, what you are seeing is the resonator, it reduces the drone of the exhaust.