I wouldn't bother trying to get an upgrade with the sat nav. Its absolute crap. When I was working for a Jeep dealership I told all my customers the same thing. Salesmen get paid extra to put it in, but I would rather see my customers happy than have a bit more money.
If you can afford to step up to a diesel, they're much more of a delight to drive. Yes they would be worth more when you sell it, but the V6 petrol has to be serviced every 12,000km and the diesel every 10,000km and servicing is slightly more expensive, so would the better resale be worth it?
The diesel certainly has the power but you'd be looking at $66,000 on road and no space to drop the price because they're so in demand.
If you don't think you'll need the towing capacity and were happy with the V6, just go the V6. The V6 limited GC's do have play I'm price so push the salesman as far as you can. At the end of the day you want to walk away knowing you got a great deal. When it comes to negotiations, the salesman will be on your side. If you don't buy, he doesn't get the commission. I have to admit, the whole 'u tell a price, salesman goes into managers room and comes back out with a red cross across your figure x2' thing is stupid but unfortunately it's a game you have to play. Don't be afraid to put dealerships against each other. I know a dealership in Brisbane that will lose money on a car just to make sure the dealership I was working for didn't get the sale.
If you start looking at demos, be warned that the 3yr/100,000km warranty started when the car was first registered, not when you buy the car.
Whatever choice you choose, you'll love the Grand Cherokee!
