Ah, and here you go:

http://en.wikipedia.org/wiki/Turnkey

So to some up:

We sell turnkey *engine conversion systems* (turnkey for short which
causes the angst perhaps), the scope of which is an engine conversion.
If we sold turnkey *vanagons*, you'd hop in and drive away. I still
appreciate that it might be confusing, but not meant to be misleading.
I use *lot's* of tech/software terms and methodologies at Bostig, it's
one of the key things that has allowed us to get where we are.

Jim Akiba