I am going to change today spark's and coolant need help

[Ryo]

Hi
I decided to change the old sparks today because the car started to shaking. I read the old one's and there is on it Nippondenso PQ16R. In manual it is written somethink totally different. What sparks to buy denso, ngk that are written down in user guide? I tried to this time bosch and ngk. Bosch was shit, ngk was fine never tried denso except those old in this hachi.
Also i am going to replace coolant because its really dark blue. Any idea what coolant to use? I used valvoline blue antifreeze coolant but now i dont know what to choose. Also i want to clean the radiator. Is there somewhere written how to do that properly.
Maybe this themes are written somewhere else but i dont know where to find it right now
Thru search i didnt find anythink also.