Some mods needed.

[Aree]

I searching trusted mods that cause no lag or are bugged and especially for this:

Trees, grass, etc.
Vehicles HD.
tymecycp or was it like that?
Skin pack

If you can give me some links I would apreciate it .

[SwatShot.]

grass/trees: clickme

HD Cars: Well, there are many cars. Best is;

tymecycp: what's that?

skin pack;

Note: It does not matter which mods you use, (unless they have a virus lol) There will be lag only if you "over-mod" your GTA. That's why l recommend making a backup. (Or SAMI - auto backup).