ISX injectors and overhead

So... I find myself with fuel in my oil and, after doing my due diligence, it seems the common consensus says I need to replace one or more injectors. I figured I'd just replace all of them once I open Pandora's box and save myself some hassle down the road. Mostly I don't know how to tell which one(s) is/are bad and doing all of them seems easiest.

My question is: just how difficult is this job? I've watched Rawze' videos on doing the overhead and there doesn't seem to be much to it as long as you have a couple different torque wrenches. But then 'someone' told me I'd have to be careful about cam wedges? Will I have to set the timing after replacing injectors?

I'm really about doing things for and by myself if and whenever possible. I'm not to keen on screwing things up because I'm too cheap. I've never cracked open a diesel, just stuck to doing things like shocks, brakes, whatever.

With slightly more brains than is required to know I'm not supposed to throw feces at others, what might my chances be of successfully replacing injectors and setting overhead be?

 

I had originally thought it might be the pump mainly because there was fuel seeping on the left (driver's side) of motor. Not a lot, just enough to make the side of the engine dirty. (it doesn't seem to be seeping there anymore).
Everything on here (and people I've actually spoken to) says injectors, though. I only know I can't go down the road with a crankcase full of fuel and even changing all the injectors has to be cheaper than an oil change once a week.

 

@Heavyd

 

Where might I find said SN if the tag is missing from the rocker cover?

 

EGR...hmmmmmm
I found out that it is, most likely, an 871.
I'll look for the ECM shortly.

 

Very pricey! Nearly $800/each plus core. I was ready for 5, maybe $600 per, but the 750-ish almost had me changing my shorts.