This resource adds custom models to the game. The only geometry data in these models is particle data. So you can use many GTA SA particle effects with them.
Usage: to change the model IDs these models replace, edit partlist.xml. To create a particle effect, create an object with respective model ID. Objects have original collisions, so you may want to disable them. Also, some particles only stream for a limited time (for example, helikill blood, riot smoke). If you want to make them keep streaming, you need to set a timer which keeps destroying and recreating the object.
Preview of some particles: http://www.youtube.com/watch?v=mifR-dyFx6s