So the stroke is when the air/fuel mixture is compressed, meaning when the connecting rod moves the piston upwards in the cylinder. Since this is compression, for N/A you want this process to be longer (high compression), and for F/I, you want this process to be shorter (low compression), right? And stroker kits one of the ways to change the stroke right?
I know this is a n00b question but what is boring and sleeving and what does that achieve? Let's say for example I want to build my motor for an N/A build, what am I looking to bore/sleeve to? (in case of numbers)
The compression stroke is when the piston is moved up in the cylinder towards the head/combustion chamber. Compression is just that, the piston is compressing the mixture of fuel/air in the combustion chamber, then when its ignited it pushes the piston back down the cylinder (Exhaust stroke). Higher compression means that there is less room in the combustion chamber for air/fuel to ignite. This is why high compression pistons have a dome or peak to them. Turbo or low compression pistons are usually dished or recessed to allow more air/fuel, usually from boosted applications b/c your flowing more air into the motor.
You could use a stroker kit to change the stroke, you could also swap in a crank with larger or smaller stroke to it. However, by changing the stroke you're also changing how far up and down the piston/rod has to travel. Then you start coming into things like rod length, location of the pin on the piston, and rod/stroke ratio, and ultimately your compression ratio. Everything is related, you change one, you have to compensate for the others.
Boring is enlarging the cylinder walls or sleeves. Ex: Stock F23 bore is 86mm, stock H22 bore is 87mm, if you overbored the stock cylinders by 1mm you could run H22 pistons and really raise the compression ratio.
Sleeving is replacing the stock cylinders with ones that are made of a stronger material than the stock units. Ex: H22/23's, K20/24's, and the F22/20C all have FRM sleeves which only allow for cast pistons to be run in them, in order to run forged aftermarket pistons, you have to resleeve these motors other wise the expanding of the forged pistons will eat up the stock sleeves in these motors. Sleeving is also a choice for when you want to overbore but can't safely do it on the stock sleeves. Meaning that at some point you can only bore out the stock cylinders so much before you run the risk of running the cylinder walls too thin.
If you're referring to that N/A build I posted, you don't have to bore or sleeve to anything. You could overbore or run stronger/thicker sleeves but its not necessary for an N/A build like that. Boring would increase the displacement and torque.