Use GTA Mod installer
1.(after you click next)Click the 3rd option
2.Click the 2nd option
3.Select where your file(s) are (you need to extract the files in the .rar fileto somewhere else before installation)
4.select where you installed Vice City
5.click yes and backup your files.
6.put "pedgrp.dat" and "weapon.dat" into your C:\GTA Vice City\data folder
7.put 'sfx.raw' and 'sfx.sdt' into your GTA VICE CITY Audio folder