installation:
use img tool to open gta3.img
replace sadler.txd and sadler.dff
open the file and replace the line included

Vehicles.ide -
543,	sadler,		sadler,		car, 		SADLER,	 	SADLER, 	null,	normal,	10,	0,	0,		-1, 0.71, 0.71,		0

handling.cfg - 
SADLER        1700.0 	4500.0 	2.7 	0.0 	0.0 	-0.05 	75 	0.7 	0.70 	0.5 	5 	250.0 	40 	20.0 	R 	D 	9.5 	0.5 	0 	35.0 	0.8 	0.08 	3.0 	0.15 	-0.10 	0.4 	0.4 	0.26 	0.20 	26000 	242040 	300004 	0 	1 	0 	

carmods.dat (add this line after the last car)
sadler, rf_b_sc_r, nto_b_tw

carcols.dat -
default works, or make your own -
first color is main body, second is the large stripe down the side

This also works in SA-MP over the yosemite, without wheel problems.
OffRoader23 2006