Installation - open "default.IDE" inside "data" folder. 

then find the line "236, vicechee, vicechee, car, CHEETAH, CHEETAH, null, ignore, 7, 7, 0, 250, 0.7" and change it to "236, vicechee, vicechee, car, CHEETAH, VCPDCHE, null, ignore, 7, 7, 0, 250, 0.7"

then copy TEXT folder inside GTA Vice City game directory, replace when asked, may not support modloader so install it in the game directory.

Important - backup the original default.IDE file of data folder and american.gxt file of TEXT folder before installing the new ones.