may not have to cut the bumper at all, every car is different.
the work you will have to do is inside the fender well. will need to remove the bump stops and stuff like that. might have to use a BFH and massage inside there, too, hard to say. every car is different, just have to play with it.
98 WS6 6 speed street car
2014 VW GLI Autobahn 6 speed
2011 BMW S1000RR