Projectors are not necessarily a pain since plenty of people so far have managed, but the issue is that there'* also work to be done to the area behind the headlights. While 2000+ Bonneville and other car guys could easily put in some headlights that were either easy or hard to make, we 87-99 Bonneville guys also have difficulty fitting in deep headlights without cutting out metal. If you do remove some metal, for which I don't see a reason to exist, you should be all set once you get past actually making some projectors fit. That part I can't make suggestions about.
94 STEi and 99 SLO