Hi
I would suggest that you don't remap. I wouldn't play around with the original computer. Around 3 yrs ago, I had fitted an external chip and had it set to give me more talk when towing my camper trailer. The thing about the chip I had fitter by Berrima Diesel is that it captures the signal after it comes from the factory computer, not before. I can disconnect it any time I want and convert it back to original. I average around 10.5lts per 100kl. When I'm towing, I'm averaging around 11.5lts per 100klm. So as you can see, it works great.
It's called; DP Chip by Berrima Diesel.
Happy motoring