Well, if you can get the old intercooler out without taking the rad out then maybe not.
If the radiator you have is in good condition then you'll be fine but if it's a little ragged then you may be better getting a new one as the new intercooler will cover part of the radiator and if it's not in good nick then you could get cooling problems.
Also, when doing the injector pump tweek, to start with only do the diaphram. If you start messing with the Star Wheel and Smoke Screw then things could get messy if you're not sure what you're up too.
Net result of over-doing it is an increased exhaust gas temperature which could burn your valves!!
Take note of the warnings on the Dodge Ram site and make a note of the position of everything you alter so you can put it back again if it doesn't work.