Remap = Written to the ECU over the original factory issued map
Pros - Written individually to your car's engine and performance. (If done correctly on a rolling road)
Undectable unless you check the files
Cons - Can not remove from the car unless you have the orginal file to swap back to. In which case you need software or to contact the company
Might be a generic map that gets loaded to your car
Pros - Can be intalled and usually varied on how you drive (most have several settings with various generic maps on)
Can be installed quickly and removed quickly
Depending on the company you can buy a new cars and the mapping company for a much smaller fee can load new maps to the device.
Cons - Generally not as tailored as a remap (Depending on what you pay and where they plug into (Various sensors)).
Initial might be a little untidy in the engine bay
Alfa 166 2.0 Twinnie - LPG and a few trick performance parts