I had mine remapped while still under warranty.

1. I knew full well it COULD void the warranty if something major went wrong that required a claim and the dealer knew/found out that it had been remapped, however I chose to ignore that and enjoy the benefits

2. There is a chance that when the dealer does work on your car they MAY accidentally over write the engine map (though its really unlikely to need doing, most times they are flashing things like sound system, heater etc)

3. A software remap is unlikely to be 'found' by the dealer, they have no reason to go looking for it, especially as it's chargeable time.

4. A reputable engine remapping firm will offer to remap the car if it is accidentally overwritten by a Dealer (mine said this to me)

If anyone wants to knows who did mine and more info, please PM me.

IMO The benefit of having the TD6 remapped are worth the potential risk. the power delivery is smoother, the torque increase is much nicer to use, and you can actually overtake other cars! Discovery 4 HSE
1998 110 TUM HS FFR Hard Top XD WOLF
1982 Series 3 Hard Top

*Gone:L462 D5 HSE LUX, L663 Defender 110 HSE, Discovery 3 HSE, 2014MY Range Rover Sport 5.0 Supercharged AB Dynamic; L405 Exec Vogue SE 4.4, 5.0 Supercharged Autobiography, Defender TDCi XS CSW, Defender TD5 HT, Vogue SE TDV8, Vogue TD6, RRSport SC 4.2V8, Classic 3.9 Vogue Auto, Land Rover Series 3 SWB

....exactly the answers I was looking for

No gurantees of course - but it's not something they would go looking for come service time, for example. Clearly, if I took it in complaining about power loss or fuel consumption - it would be differnet.

Gonna have to go for it.