I am not an expert or anything, I don't have a degree in anything, and I am probly the youngest forum member; but here is my take on it...
Look at all the blown motors we have seen. These motors are designed to make 500hp, if they could safely make 501hp dodge would have done it. It's not hard to see that F/I or Nx severely reduces the amount of time these motors survive. There is no "safe" boost or Nx shot, your playing with probabilities, and every time you up your Hp, you up the chance of a major failure proportionally.
Whats all that mean? If you don't have the money to rebuild your motor, then don't play the game. I have a Nx kit and slicks sitting here, I love Nx and I think it's the answer to getting these 5000lb trucks moving off the line, but I am not going to blow my motor and have to make payment on a truck I can't drive. I have seen people on here paying on a truck that just sits, not to mention the ones that use there trucks as a daily driver that are left w/o a ride.
You can drop in basic parts to forge you motor for 3,000$ (mains, pistons, and rods). Now if you blow up and put a rod through the block(just about every blown motor I have seen has done this) your looking at between 5k and 10k IF you can find a new motor, and that just to get it back to stock!
To me it's obvious, if you don't have money then don't play.