I'm gonna install headers, free flow intake, and a after market exhaust on the car but after that what else should i upgrade or put in it, if the answer is NOS then what do i need to do to prepare my engine for it and how often will i need to rebuild my motor
AT BEST, you'll see about 10-15 horsepower, at peak rpm. That's all the parts combined. And that's only 5000rpm or higher. And basically no gains in torque. And since torque is what actually moves the car, not horsepower....that's what you want to focus on.
Horsepower wins brags. Torque wins drags.
For normal driving around, you'll be around 2500-3000 rpm. At this range, you will see little to no gain. You may even lose power.
So, your car will most likely maintain it's current performance, or go slower.
But, you'll drive it harder, because you want to feel the new performance, so, to you...it will feel faster. It is, in fact, not.
This has been proven countless times on dynos. Advertisers advertise only the peak output. Not the average output, which is what actually matters.
Just like advertising your car can go 160mph. How often will you actually do that? Basically never. So it's completely worthless advertising.
If you want a nitrous system, get new rods, pistons, rebuild the head and block, basically spend about $5000-$7000 building the engine properly. Otherwise, it's just a matter of time before it blows up.