you should be able to swap the 200sx bumper without any issues. note that the 98 200sx and 99 sentra bumpers will look very different and the headlights and grill change as well.
I have a 98 200sx and I had to get a replacement bumper because somone backed into my car. My new bumper is the one that is currently on your car. Maby Ill shoot some pics today.
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