I drive a D40 which already has a front-mount intercooler. Its fan might be a little different to yours as it's been designed to handle the heat from the engine coolant, gearbox oil cooler, air conditioning condensor and the intercooler - so you might need to look at a thermal fan.
You could try getting a chip through eBay, or second-hand from one of the guys here. There are times when people sell their Navaras and since some of the chips are vehicle-specific they sometimes remove the chip and sell it separately.
If it's your first turbo-powered car, there's one vital piece of advice to give you: allow your turbo to cool before shutting down your engine. Hot turbos cook the oil that's inside the bearings in the turbo, causing the bearings to self-destruct.
To avoid this, choose any or all of these options:
* Plan your journey so that the last couple of km are driven very gently. The turbo will naturally cool down and you can just turn off your engine at your destination.
* After running the engine hard, sit in the cabin for 2 minutes with the engine idling before turning it off and leaving. That's boring, and you'll quickly change to the previous option.
* Fit a turbo timer. While not strictly legal and costing some $, this will achieve the second option without you having to sit there.
* Fit an EGT-controlled turbo timer. Still not legal, but smarter - it will keep the engine running until the thing is cool enough. Requires the combination of two kits from Jaycar.
Hope that helps!
