Help clear some things up for me

[My LT4 Z]

Well, I talked to my mechanic and he said when he pulled off the oil pan to change the pump, my car has new, possibly forged, crank and connecting rods. So that was all it took to convince me that I can run nitrous without worries (hopefully). I was reading the tech article and was wondering if anyone can clear a few thing up for me....

If your motor makes a lot of hp-over 400 by itself,or if you run a lot of nitrous-200 hp or more,it is smart to run two seperate fuel pumps. One should be for the motor and one for the nitrous kit. You may even have to run two 1/2" fuel lines depending on how much hp your motor and kit can produce

So my motor is a cammed LT4, LTs, an electric pump and a pulley to delete the A/C, ported intake and 58mm TB, and a few other goodies, so I expect to be making over 400 hp, but I only plan to run a 100-150 shot, so will two fuel pumps still be needed? And can I just mount the second one by drilling a hole in the trunk next to the stock pump?

How to set timing:For every 50 hp in Nitrous you add to a motor,you must retard timing by 1-1/2 to 2 degrees in order not to damage parts. For a 150 hp kit,you would take 4-1/2 to 6 degrees of timing out.

Ok I dont really understand this at all...Is timing controled by the computer in this sence, or is this refering to the timing of the cam in respect to the crankshaft? If its the second, then wouldnt retarding the timing cause the engine to looser power when nitrous is not activated?

Finally, the custom cam I have in the motor now is mid-230s duration, 111 lsa, and .57x lift (.60x with 1.6 rockers), so its for a N/A engine, but will I still see the same performance out of a nitrous setup and a cam this big?