Dude youre using the 4g18 engine or campro onwards?
No comment on the lsd gearbox, no experience there.
1.Bigger pistons as in bore or what? If bore then you'll have a bigger surface for combustion a.k.a more power. If you mean HIGHER compression then im not sure how to explain haha 
2.No idea in cam tuning, anyone care to help?
3.LIGHTENED crank pulley: A CRANK pulley is a PULLEY at the CRANKSHAFT to guide whatever belts that need to be driven, a lighter one just reduces weight and makes it easier to rotate. Like for exapmle imagine ur bicycle carbon fiber wheels instead of metal ones lah 
4.LIGHTEND cam pulley: A CAMSHAFT pulley is a PULLEY at the CAMSHAFT that has to do with timing if im not mistake?* Aftermarket ones usualyl have markings to either retard or advance the timing. If its lighter than stock, the theory is same as above. It spins easier.
5.Changing the head is the middle part of your engine, the top part is the cam cover where ur cams are kept and where you pour your minyak in when you service your car. Then in the middle is ur head (No not literally your head ) where the ports are. There are 2 types of ports. The exhaust and inake port. They both are basically holes where the exhaust gas enter and where the fresh air goes in to get combusted. By swapping the head that means lets say...
A civic b-series engine. You can take the 'head' from a type-r civic and bolt it into your normal b-series engine and get performance!
Why though?
Not all heads are the same. Basically there are some the lubang is bigger, or better shaped, or specially designed like the type-r head. Its meant for more air to go in and out.
If you want to get better performance out of your waja N/A I would recomend the basic upgrades:
1.Intake (K&N, HKS, ApexI up to you. I dont trust the unbranded ones tho)
2.Exhaust system, again this is up to you. I have a 'cap ayam' exhaust system in my car but it does give performance. I would also recomend branded exhaust's if your budjet allows
3.Spark plug cables
4.Better spark plugs? *maybe, again up to you *
5.Some kind of air/fuel tuning device. Apexi SAFC or a E-manage would be a good start...
Hey hope i've helped dude! :D
