For what it's worth - curious me wanted to know how the holder on my 97 was fastened. When I unscrewed the two screws that held the plate and removed it, the plate holder itself appeared to be held in place with plastic rivets. There was no removing the rivets without destroying them and so I took my drill and off they came.
When it was apart the rivets looked similar to drywall bolts that flare on the backside - like you said there's not much back there. So I cruised around without a front license (sure looks nice) until the local cop pulled me over and insisted I put it back on.
I couldn't find the plastic rivets and ended up using those plastic fasteners used to hold interior door trim in place. So far they're holding.
I just purchased the front license plate bracket kit for the 1996 SL1
> 4 door. I found that the front bumper has holes already drilled in the
> bumper proper that are aligned with the holes in the bracket. However,
> only ONE of these 5 holes has any subtantial backing as best as I can
> tell. The top row of holes has two holes in it, and these line up with
> the holes in a license plate. The right one (as viewed from the front)
> is in front of a metal strip of some kind, and if I drill through that
> strip (which is behind the bumper), I have a firm base for a machine
> screw to tap into. Everything else, including the three holes that
> appear to be to mount just the bracket itself to the car, as opposed
> to mounting both the plate and bracket, all just pass through the
> "flexible" bumper material into air. This includes the left license
> plate hole in the top row.
>
> Can anyone tell me how this kit, or a front license plate, is supposed
> to install? I'm concerned that even if I manage to find nuts for the
> other screws, and get them placed behind the bumper for those screws,
> that the bumper material is not a solid mount. Additionally, it's not
> going to be easy to get my hand back there to get those nuts on. But,
> I don't trust having just one machine screw through the metal strip > hold it all on.
>
> Any solutions, other than taking it to the dealer?
>
> Jim