by front top lip do you mean the front bar?
my front bar / spoiler had mounting points moulded into it so I could screw the reo bar into it.
the lower lip had no holes drilled. I drilled 6 points through the front bar and lower lip and screwed them together using some large diameter washers on each side.
My c pillar panels needed to have some glass removed from them too, I used a belt sander, drill and file for different areas depending on the location, how easy it was to get a tool in there and how much material had to be removed.
good luck with it. do you have a thread where you are posting pics?
seeing others progress is good inspiration.