I added Aussie Lockers to the front and rear of my very stock 89 Toy P/U and 31" bias swampers (read: LOUD) and the thing will climb trees now! The lockers were about $250.00 for the front and about $260.00 for the rear, tires (new) were about $550.00 for four. so for a wee bit over a grand, I have a vehicle that handles great off road.
Sorry guys, I don't presently have a VX to relate to, but I'm scraping together the cash and looking! But I do have a few years off-roading experience wheeling and building them.
R2M