Since I'm working on my first conversion, have a couple of questions. Whay kind of metal is used to make these die cast? How hard is to drill into this? Which would you rather do--glue on an antenna, or drill a small hole and glue it in from the underside?

Its a white pot metal. Its very soft (as a metal. Its still hard, but its a soft metal). Drill the antenna hole.

Drill like Mike said, it would have a better look. Dont worry about the metal, I have drilled into countless bodies

I've done anything and everything you can imagine to any metal you can imagine.

Welded aluminum, melted aluminum, made zinc spontaneously combust...and so on.