Noob question for Gmax/3D's Max

[-XeNoN-]

Hi all, im trying to import new engines for some ship that already has fx_engine_emmiter ones, is it safe to delete those or i can add "over" them new ones like vanilla's fx_xtc_engine_red for example?
Also do i need to clone each fx_engine_emmiter to the positions where i want to add new ones?

[Killjaeden]

engine emitters are for smoke and flare effects (vanilla has no flares and almost invisible smoke) - particles in short.

the exhaust effect is the exhaust flame you see

place the exhausteffect everywhere there is an engine. Place only 2-3 engine emitters, particles kill fps pretty effectively