1)Open GTA3.img and replace infernus.dff and txd with the ones you downloaded


2)Replace the Handling line with this:

INFERNUS 1600.0 2.0 4.4 1.1 0.0 0.0 -0.3 70 1.2 0.86 0.42 5 240.0 25.0 R P 11.0 0.52 0 30.0 2.2 0.1 0.30 0.9 95000 0.25 -0.14 0.5 8181 0 1


3) Open carcols.dat and replace Police line with this

infernus, 3,3, 6,6, 57,57, 1,1, 60,60, 74,74, 70,70, 26,26

4)replace infernus.col inside vehicles.col file using col editor2