Wether you need a remap depends on what you are doing with it, what do you have in mind, ie what sort of gains are you looking for and on what spec engine?

Dry systems fall into 3 categories:
1) they rely on the ecu to provide more fuel my being programmed for the nitrous system, potentially ok but has a few hazzards

2) rely on the fuel pressure regulator being "fooled" into adding more fuel by upping the pressure, VERY dangerous dont go near it

3) dont add any more fuel at all, this is about as useful as driving your car into a river.




So unless its a very specialist application you will be looking for a wet bascially mate.



Give me some more details about the car and i can give you more details about nitrousing it