SRt3 is a very big mod for SA, It retextures everything you can see, and play with, the landscape, the dynamics objects, the trees, the grass, the cities ! Every City Is Retextured in the final version that's coming for the 1st September 2006 !
The mod is in development for 1 year new, and will have approximately 500Mo. More detailled informations may come later, when i'll create my GTAF topic