I have just bought a pair of xenon headlights for my 13my freelander, would it be possible to fit a resister in the line rather than put them on autologic to re-program as then if I sold the car at a later date it would not have to be re-programed.

Do it properly and have them coded, sell your old lights and enjoy the xenons while you have the car.

Fit some tinted lenses too, that way you wont blind everyone, still as long as you can see more, sod oncoming traffic

Not a fan of xenon then!