MARK C scooby

hi im just about to buy a my99 scoob. its my first one and i need help if any has any pointers on the decat and ecu it would help as they have both been done about six days apart just need to know if any damage can be caused if the decat is run before its mapped cheers, mark,
and also general pointers and tip would help on what to look for on the car, cheers.