[JKnight]

Seems like you guys are on the same page with what JRouche was explaining with using the silicon boots.

I believe I saw some large diameter grommet-type things in an Earls catalog that you could put in the trunk floor and pass the metal pipe through if you didn't want to weld it solid to the floor. Might help if you ever wanted to modify, clean, or re-coat the pipe. I believe they were supposed to be water and fume tight. I was just browsing through it so I don't remember all of the details, but I'll look through it again and find it.