I saw some chops here and the suneffect from them it's amazing realistic...who can make a tut with his method?

do you mean like a sunset?
or reflections on the car?

If it's the first then its just a case of adding a photo filter, playing round with the opacity of it and playing around with brightness and contrast....

However this can look very fake if you don't get it right

car reflections

ok, its no different to any other brushing really

I think there used to be a tutorial, about how to get the exact right effect,
i'll have to have a look around
however, just with any brushing - find reference, and copy the colours across and brush them on

i tried to brush it on my rx-7 but it's like crap lol ( left side.. the right sun effect it's better imo, check it out )

give some example of that sun effect, just post some image that have that kind of effect so that people know exactly what you´re looking for, it would be way easier to know what you mean then