1) Will need more info about the leak to offer any insight, but no - nothing should be leaking.

2) Stocks shocks are close to $500 each if you can still get them (not sure if they are available). Pretty much ALL OEM parts are extraordinarily expensive, now that Isuzu pulled out of the US market. We love our VX's, but you need to go into this with your eyes wide open - Isuzu support has vaporized in a practical sense. They will still get you parts if you need them - but they may take a month and the prices can get ridiculous. On the other hand, with so many Troppers and Amigos on the road, there are a LOT of aftermarket part supplies, which is kinda nice, because they are often cheaper than what Isuzu used to charge for OEM parts.

3) That mileage is range is great for combined driving with an emphasis on highway driving. If he has bigger than normal tires, then that number is an under-estimation of the average mileage. You can't make a silk purse from a sow's ear - the VX's mileage just ain't that good.