got a 2.1 zetec turbo for my mk4 escort

just wondering, when i plumb it all up with the bits and pieces recommended on that chardcars site do i just take it to a rollin road and they remap the ecu? or what happens?? lol im a n00b at this bit

2nd bit, currently my mk4 esct has xr2i 1.6 cvh EFi loom and engine in, would it be better to get a OFAC loom and ecu and re-splice that in instead of using OFAB?

many thanks